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My Chemical-Free House

A Guide to Creating a Healthy Home

  • Healthy Building
    • Insulation
    • Windows & Window Treatments
    • Glues & Caulks
    • Grout & Mortar
    • Drywall
      • Drywall Mud & Wall Texture
    • Showers
    • Doors
    • Pressed Wood Products
    • Sheathing & Subfloor
    • Pipes
    • Alternative Building Systems
    • Non-Toxic Prefabs
    • Building for the Chemically Sensitive
    • How to Test Materials
  • Healthy Interiors
    • Flooring
      • Gym Flooring
      • Flooring Underlayment
    • Kitchen Cabinets
    • Countertops
    • Mattresses
    • Sofas
    • Leather Furniture
    • Desks and Chairs
    • Sealers
      • Paint
      • Mineral Paints
      • Linseed & Tung Oil
      • Natural Wood Pigments
      • Natural Plaster
      • Natural Countertop Sealers
      • Concrete Sealers
      • Wood Finishes
    • Bathroom
      • Bathroom Vanities
    • Rugs
    • Wallpaper
    • Kitchen Appliances
    • Heaters
    • Reduce Flame Retardants
    • Reduce New Home Offgassing
    • Reduce Fragrance & Smoke
    • Air Purifiers for VOCs
    • Cleaning Products & Air Fresheners
    • Personal Care Products
    • Green Certifications
    • Gift Guide
  • Healthy exteriors/gardens
    • Decking Materials
    • Deck Stains
    • Deck Cleaners
    • Exterior Paints
    • Sealant for Concrete Birdbaths
  • Tiny Homes and Trailers
    • List: Simple Homes & Shelters
    • List: Trailers & RVs
    • List: Emergency Housing
    • Cargo Van Conversion
    • All Metal Tiny Home
    • Simple Insulated Shelter
    • All Aluminum Travel Trailer
    • Cargo Trailer Conversion
    • Teardrop Trailer
    • Tiny House Systems
    • Flooring for Vans, Trailers
    • Composting Toilets
    • How to Offgas that New Car Smell
    • Building for Chemically Sensitivity
  • Mold-Free Building
    • A Detailed Mold Preventative Build
    • The Causes of Mold in Tiny Houses
    • How “High Performance” can Help Prevent Mold
  • Mold-Free Interiors
    • Mold Testing Overview
    • Air Purifiers for Mold
    • Ozone to Kill Mold
  • Mold Avoidance Paradigm
    • Decon your Car
    • Camping Gear
    • Planning a Sabbatical
    • Traveling with Environmental Sensitivities
    • Locations Effect Ebook
    • The Locations Effect – Canadian Locations
    • The Locations Effect – Caribbean Campsites
    • Interview: Healing MCS with Mold Avoidance

Mold-Free Interiors

How to Choose a Hotel When you Have Chemical Sensitivities (And Mold Sensitivity)

January 6, 2022 by Corinne 4 Comments

Choosing a hotel, some tips

This is what I have used to find good hotels, especially important when you are booking something in another country and need your first bet to be a good (enough) one.

Never override your own senses/reactions with “the rules” but this has been helpful with knowing where to start. Lots of fails and trial and error for me.

– Go as new as you can. In tropical countries, it’s even more important to choose new. Brand new if you can find it. Buildings do not hold up well in the tropics.

– In countries I really want to go to, I’m watching for opening dates of hotels I have my eyes on.

– Big brands can be better. Marriot, Hilton, and Hyatt, and some European brands too can be better built. Though I would not choose an older big name over a newer local hotel.

[Read more…] about How to Choose a Hotel When you Have Chemical Sensitivities (And Mold Sensitivity)

Filed Under: Mold Avoidance Paradigm, Mold-Free Interiors

Non-Toxic Grout Sealer Options

November 30, 2021 by Corinne 6 Comments

Whether you need a grout sealer depends very much on the situation. A grout sealer could actually do more harm than good.

For that reason, I will list out the non-toxic sealer options by application and then by type of sealer.

The densifiers are the most tolerable least toxic option, they are a very benign product. Topcoats of acrylic or polyurethane do have some odor and offgassing at first, but the offgassing comes to completion in a short time.

There is also the possibility of going with a natural product, some natural penetrating oils can be used on concrete grout.

[Read more…] about Non-Toxic Grout Sealer Options

Filed Under: Healthy Building, Healthy Interiors, Mold-Free Interiors

Mattresses for the Chemically Sensitive | A Complete Guide for 2023

February 21, 2021 by Corinne 167 Comments

This post started out with my journey to find the best mattress that suited my own extreme sensitivities. There are so many more options now. Still, many I don’t think are good enough.

We will look at my top picks for the best healthy spring mattresses (no latex or polyurethane) with price comparison (2023), all wool mattresses, and other futons, and why I don’t use natural latex.

There is no all-around “best” mattress for those with sensitivities. Sensitive folks can have a hard time with any of the following main materials used: cotton, wool, hemp, natural latex, and polyurethane. You will have to find out which materials work for you.

The article includes a look at more unusual options for those who don’t do well with any of those main materials, or who just want something simple.

[Read more…] about Mattresses for the Chemically Sensitive | A Complete Guide for 2023

Filed Under: Healthy Interiors, Mold-Free Interiors Tagged With: healthy furnishings, healthy interiors, mold prevention

Emergency Housing for Chemical and Mold Sensitivity MCS / CIRS

April 2, 2020 by Corinne 24 Comments

Emergency Housing for those with Chemical Sensitivities (MCS) and Mold Sensitivity

Here is a list of some housing ideas for those with environmental sensitivities needing immediate or temporary safe housing.

This post contains affiliate links. Upon purchase, I earn a small commission at no extra cost to you.

KOA Cabins

KOA cabins are located across the US and Canada. The cabins are made from mostly safe materials (mostly wood) and have been reported to be good places to stay for those who are environmentally sensitive.

Ask if the wood has been stained recently. The bathrooms are separate and may or may not be mold-free, depending on the location.

Recently I’m hearing reports of these having gone moldy. If the foundation or roof is not done right there is a high chance these could go moldy. Often newer is better for mold.

Home Made Tents

Regular tents can be difficult because of the chemicals used on the fabrics, the lack of insulation and the tendency for them to go musty very easily and be a lot of work with the airing out and drying out.

I have a preferred tent which is an off-the-ground tent in my post on camping gear. Here are some alternatives:

Reflectix Tent 

Reflectix provides some R-value and reflects light so that should work in a lot of different climates, though the seams will reduce the insulative value and add more glue and more potential for leaks. There are simpler designs for the structure that will reduce seams.

You can’t buy these – you would have to look online for the metal structure, then buy the Reflectix, foam, aluminum tape, and duct tape and then have someone make it for you. The tape may make this intolerable for some. And this also lacks airflow. 

You would also make at least one triangle out of polyethylene or an EVA Shower Liner so that you have some light. But have a flap of Reflectix over it that you open and close over this “window”.

Plastic Tent

A woman sitting outside of a tent that she made from Tyvek plastic
Kim’s tent via Paradigm Chage.org

Kim was severely sensitive to chemicals. She made a tent out of Tyvek which she tolerated well when extremely reactive. She explains how to make it here. Through extreme mold avoidance, Kim made a full recovery.

This is a plastic used as house wrap.

There are so many options here on what you can build an emergency tent out of. It all depends on what you can tolerate.

It may not last forever but it may give you some time to find another option or even bring down your MCS which will open up options. 

Other materials you could use: polyethylene, tarps, even hemp fabric if you are not expecting rain and don’t have high humidity.

Foam Tent

A A frame foam box that I set up inside my cargo trailer for sleeping in

When Sara was an extreme reactor (also now recovered), she made a simple structure out of XPS foam boards. The two-inch boards of XPS (usually Owens Corning brand can be found easily) have a high insulative value.

She arranged them in a tent shape, the groves in the edges holding them together. Rocks at the base pressing them together. Of course, you could use tape if you can tolerate that or put plastic over the whole thing.

Above is my version made of polyiso foam. This is a “foam tent” used inside a non-insulated trailer that was cold and still offgassing.

I hooked up a Panasonic ERV and ran fresh air into the tent at night via a 4-inch aluminum tube. The opposite end of the tent had a 4-inch hole for air to exit.

This is a highly effective way to deal with offgassing – fresh air is pouring through, though it can be difficult to control the temperature and humidity this way. 

Coroplast Tent

This Youtuber built a foldable shelter out of the safer plastic Coroplast. The downside is the amount of tape needed to form a shelter like this.

Simple Wood and Foam Shelter

The actual wood frame which was the cover of my foam shelter

Inspired by the idea of a foam shelter, I have made two highly insulated shelters with ridged foam, raised off the ground and covered in a tarp.

A wood structure like mine pictured above, may be needed to protect from wind and snow. 

The frame was covered with a tarp and inside on the plywood platform was a box made out of foam. This shelter worked extremely well though there are things to keep an eye on in the long term.

Here are some video tours and here is a post devoted just to this shelter (the second one had no wood framing above, just a tarp).

A digital sketch up of a wood A frame on a platform that my foam shelter went inside.

The whole thing was completed with some volunteer and some paid labor for 1000 CAD. 

Such a robust frame is not always necessary. You can build the plywood platform, with foam box on top and simply string a tarp over this if you don’t have strong winds or lots of snow. 

This is the same structure with a tarp over it and the XPS foam box secured with tape inside. The design can be improved by fixing the tarp, painting the foam structure and using clear tape. Please contact me for details if you want help setting something like this up.  

Here’s another example of a foam box. Just don’t put it right on the ground like they did here, and you want another cover on it. This is polyethylene foam which is much more unusual. 

Insulated/Aluminum Tents

These WeatherHyde tents are insulated and the foil on the inside will also block most of the VOCs from the fabric on the outside.

They say you can sleep in them down to 0 degrees Celsius.

They are 600 USD.

They look like they would have problems with airflow and condensation inside. As well as being straight on the ground, but they may work for some people. 

The shift pod for 1300 USD is similar but with the reflective layer on the outside.

This will help reflect the sun and keep cool in sunny weather when there is no shade.

But I don’t know how this will perform well with condensation inside.

The best of the typical tents have an internal mesh layer, then a gap with a rainfly on top. If you don’t use that system you usually end up with condensation. 

There are other similar tents cropping up that were designed for Burning Man festival.

For a lot less you can get a simple aluminum-lined small sleeping tent. It’s not insulated but the aluminum on the inside is more tolerable than the usual tent materials and does reflect heat inside. 

Regular Tent

My tent outside an cob house at OUR ecovillage
My first tent CC BY-NC-SA

There is no perfectly chemical-free tent, The most tolerable brands include Ozark, Big Agnes, REI, LL Bean, Colman, and Lightspeed. Everyone is different. 

Moonlight makes flame retardant-free tents coated with silicone on the outside and polyurethane on the inside.

Here is my post on safer camping gear which goes through all the major brands that folks do well with.

In the post, I also discuss canvas cotton and hemp for really dry climates (or temporary use) which may be where the most sensitive need to start.

I would also check out the cuben fiber tents mentioned in the camping post.

Yurts & Huts

A green plastic yurt on a platform at OUR Ecovillage on Vancouver Island
Me at a yurt at OUR Ecovillage CC BY-NC-SA

Yurts are often tricky for a few reasons. They are normally made out of PVC which takes time to offgas.

On top of that they are difficult to insulate, although one could just use them as an uninsulated tent.

The wooden framing can be susceptible to mold if there is a lot of condensation inside or with high humidity inside, which can happen when heating up a small space.

The wood also might be treated and could cause reactions. There are yurts that have metal framing which may be preferable for some people.

Here is an example of a metal-framed yurt.

You can create your own outer yurt cover by using a more tolerable material, although it will not be as long-lasting as PVC.

You can use materials used to make a tent, or polyethylene sheets that are used for greenhouses, or tarps. You could also go truly traditional and use hides.

One really positive design feature of yurts is that they are lifted off the ground on a platform. All metal yurts may work for some. I have looked at those in the post on simple shelters. 

These glamping tents by sweet water bungalows are PVC, with a canvas top (prone to mustiness), but the guide and framing could be used to create a tent with a plastic of your choosing.

Just keep in mind polyethylene is not as durable, but is less toxic. 

I wouldn’t use canvas for anything other than a short and dry camping trip but without the breathable roof these are prone to condensation.

Conestoga huts have a simple design for a little hut/glorified tent. A simple design that goes up fast is a big benefit.

I have not been able to review these plans for mold preventative building, but it’s an interesting design. If you have the plans for these will do a free review.

If you don’t insulate this it shouldn’t be a problem. If you do want to try these with insulation please reach out to me or an expert in building science. I am not presuming these are a mold-safe design.

Simple Metal SIPS Shelter

Two walls going up of the small metal SIPS house

You can easily put together click-together metal SIPs to make a fast, clean and fairly durable structure.

SIPS are structurally integrated panels. Metal SIPS are made of steel-styrofoam-steel sandwiched together. A highly tolerable material for those with severe sensitivities.

Because these are structural you don’t need to build a frame. Pour a concrete slab, and then once you have the panels it’s fast.

To create a long-lasting structure you would add siding but if you need something done fast, just put it up.

This little shelter is made with Structural Building Systems panels.

A small metal SIPS house in the desert

Sheds

Steel sheds can be bought from Amazon or hardware stores for 700-1000 dollars.

You will also need to build a foundation (you could also just leave it as gravel), pay for labor to set it up, caulk the whole structure and likely put in some insulation.

For everything you need to know about setting up a shed to live in see this post by EI Wellspring.

Sheds are not as easy to take down as you would expect.

There are also wooden and plastic sheds. I have seen some good little wooden shed kits made of solid wood.

Raise them off the ground and cover with a tarp above that is not touching the shed.

I like cedarshed.com for those who can tolerate cedar because it’s a highly rot-resistant wood.

Check out the wood first, see how it was stored and test it for reactions. 

Hard plastic sheds will work for many people. The more flexible the plastic the more it offgasses. PVC should be avoided where possible.

Glass Enclosures 

A greenhouse in the desert used as a shelter
www.buildahealthyhouse.com

A greenhouse can be used for backup shelter, it gets very hot when the sun hits them in warmer seasons and can dip really low at night in colder temps.

But some people have used them successfully. Margaret (another person who used this strategy to heal and make it back to indoor housing) talks about her experience with them here (her greenhouse pictured above). 

Other glass/metal enclosures brands are Handi Hut and Four Season.

Small sketch up for a glass and foam stucture with glass as the interior walls and foam on the outside with a tarp over it.

I designed an all-glass on the interior shelter with insulation on the outside. This was designed for a time that I could not have metal or wood inside touching me.

The walls and floor were glass. The ceiling would be easier to make out of metal.

The shelter was raised off the ground on a platform. Outside of the glass was 2 inches of foam insulation. To hold this insulation on, the exterior framing (outside of the foam layer) was attached by drilling through the foam and glass. The foam needs to be airtight to the glass. A tarp should cover the shelter.

Back of a Pick-Up Truck

Try and find an aluminum canopy for the back of the truck, which is the best-tolerated type.

The bed liner may need to be offgassed or can be covered with Reflectix.

If ordering a brand new truck you can request no liner.

Cargo Trailer

A cargo trailer that I converted into a RV

Details on converting a cargo trailer safe in this post. 

The company WeRoll can customize these and they have more robust roof lines compared to the standard models. 

Ambulances and Refrigerated Trucks

A decommissioned ambulance used as an RV home

The benefit to these two options is that they are already insulated and ready to go.

A decommissioned ambulance is insulated and offgassed since they already have quite a few years on them by the time the government sells them off.

Refrigerated trucks could be found either new or used and they are well insulated and also ready to go.

If you went new you would have to check out the offgassing levels to see if it suits you, but I would expect it to last longer.

Creating a Safe-Room in Your House 

To create a non-toxic room in your home you can use Denny Foil, or heavy-duty aluminum foil on the walls/ceiling/floor.

These materials block VOCs (chemicals/toxins including mold).

Heavy-duty aluminum foil is much easier to work with than the type used in cooking. You may need several layers to totally block smells. 

You want to use green Painting Tape for this as it will not damage the walls and is easy to remove – a healthy person could rip off/take down the whole room is probably 20-30 min (small room). The blue tape is toxic so I wouldn’t use that. You could use aluminum tape but it is very sticky and will leave a residue and will be hard to take off. Aluminum tape also smells and offgasses more than green tape.  

I would not do this where you have colder air inside than outside (AC use). 

Cover outlets. As for light fixtures, I would go around them. 

The only thing in the room should be clean bedding i.e. a new non-toxic mattress or camping cot (etc). New non-toxic bedding and pillow.

Be careful that when you open the window or the door that the air coming in might not be good, so this won’t be a long-term solution. 

If you can’t foil the walls you can make a room within a room and use positive pressure as explained here in this post. The picture above shows how pressurized rooms keep out contaminants.

You can use foam, plastic or any airtight material. Isolate that by using positive pressure which will work to reduce chemicals like offgassing.

That can be a solution for someone extremely sensitive who has trouble with offgassing (when the issue is offgassing rather than mold).

You can find more information by researching isolation rooms. 

Ecovillages

A cob house at OUR Ecovillage on Vancouver Island
A cob house at OUR Ecovillage CC BY-NC-SA

Staying in a cob house (or straw bale, adobe, light straw-clay house) can be a really good option 

Ecovillages may rent out rooms in natural homes and there is a possibility of getting in on the communal meal plan as well. Search for some in your area and ask about monthly stays.

I have seen some natural homes listed on AirBnB as well as on lists of intentional communities/ecovillages. 

Always ask about propane, natural gas, cleaning products, and water damage. I have found that is wet/cold climates cob and similar materials do not hold up to mold after a few years.

Slabs and roofs often have mistakes that lead to mold. Green roofs can be very problematic. Amateur built houses are especially prone to mistakes that lead to mold.

This type of building is best when raised off the ground, or with a simple roof, otherwise, don’t bank on this being safe if more than 1-3 years old. 

Ecovillages are also a good place to set up a tent where you might have access to outdoor bathrooms and kitchens that are more MCS safe than campgrounds.

It may also be a safer environment for those traveling solo. I have used the Intentional Communities website, Google for places near you, and the site wwoofing.

If you have physical energy you can work on a wwoofing site in exchange for free rent (camping or small cabin usually) and often food.

Another option for those who have energy to do work is remote cabins that are advertised on Craigslist where you do some house and yard work in exchange for rent. The cabins might not be safe, but this could be a free spot to camp or live in a trailer. 

Other Emergency Housing

We should have emergency and long-term safe housing for people with MCS, but in reality, there is very little.

Check out the Environmental Health Association of Québec if you are a Quebecer. 

For housing listings in the US and Canada, join EI Safe Housing on Facebook. 

When I come across AirBnBs, hotels and short-term rentals that look safe I list them on my Pinterest page.

While many turn to Airbnb or other short-term rentals, in the beginning, this can be a difficult and sometimes impossible road if one is super sensitive and/or masked to mold. 

Corinne Segura is a Building Biologist Practitioner with 8 years of experience helping others create healthy homes.

I spent two years in tents and small structures in order to heal from extreme chemical sensitivity. 


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Filed Under: Healthy Interiors, Mold-Free Interiors, Tiny Homes and Trailers Tagged With: camping, emergency housing, mold avoidance paradigm, tiny homes and trailers

Dilution Table for Hydrogen Peroxide

March 18, 2020 by Corinne 50 Comments

How to Dilute 35%, 34% or 29%, 12%, 10%, and 6% Hydrogen Peroxide (H2O2) Down to 3%, 1%, 0.5%, 0.2% and 0.1%

This method is not precise especially at higher concentrations of HP because we are using the 1 part HP as 1 part water. It still is accurate enough for cleaning purposes.

This post contains affiliate links. Upon purchase, I earn a commission at no extra cost to you.

a pair of latex gloves, safety goggles, ear plugs, and a respirator

Personal Safety Equipment Should be Used!

Goggles, gloves, and protective clothing. (Source & Source).


Dilution Table

Dilute 35% Hydrogen Peroxide

1 part 35% H2O2 to 1 part water (math is 35/2) = 17.5% Hydrogen Peroxide

1 part 35% H2O2 to 2 parts water is 35/3 = 11.7% Hydrogen Peroxide

1 part 35% H2O2 to 3 parts water is 35/4 = 8.75% Hydrogen Peroxide

1 part 35% H2O2 to 4 parts water is 35/5 = 7% Hydrogen Peroxide

1 part 35% H2O2 to 5 parts water is 35/6 = 5.83% Hydrogen Peroxide

1 part 35% H2O2 to 6 parts water is 35/7 = 5% Hydrogen Peroxide

1 part 35% H2O2 to 7 parts water is 35/8 = 4.4% Hydrogen Peroxide

1 part 35% H2O2 to 8 parts water is 35/9 – 3.9% Hydrogen Peroxide

1 part 35% H2O2 to 9 parts water is 35/10 = 3.5% Hydrogen Peroxide

1 part 35% H2O2 to 10 parts water is 35/11 = 3.18% Hydrogen Peroxide

1 part 35% H2O2 to 13 parts water is 35/14 = 2.5% Hydrogen Peroxide

1 part 35% H2O2 to 34 parts water is 35/35 = 1% Hydrogen Peroxide

1 part 35% H2O2 to 69 parts water is 35/70 = 0.5% Hydrogen Peroxide

Another way to make 1 gallon of 3% Hydrogen Peroxide: Mix 1 and a quarter cup of 35% HP with 14 and three quarter cups of water.


Dilution Table

Dilute 34% Hydrogen Peroxide

1 part 34% H2O2 to 4 parts water = 6.8% Hydrogen Peroxide

1 part 34% H2O2 to 4.5 parts water = 6% Hydrogen Peroxide

1 part 34% H2O2 to 8 parts water = 3.7% Hydrogen Peroxide

1 part 34% H2O2 to 9 parts water = 3.4 % Hydrogen Peroxide

1 part 34% H2O2 to 10 parts water = 3% Hydrogen Peroxide

Make 1 gallon of 3% Hydrogen Peroxide: Mix just a touch under 1.5 cups 34% HP with 14.5 cups of water.


Dilution Table

Dilute 29% Hydrogen Peroxide

1 part 29% H2O2 to 1 part water = 14.5% Hydrogen Peroxide

1 part 29% H2O2 to 2 parts water = 9.6% Hydrogen Peroxide

1 part 29% H2O2 to 3 parts water = 7.25% Hydrogen Peroxide

1 part 29% H2O2 to 4 parts water = 5.8% Hydrogen Peroxide

1 part 29% H2O2 to 8 parts water = 3.2% Hydrogen Peroxide

1 part 29% H2O2 to 9 parts water = 2.9% Hydrogen Peroxide

How to Make a Gallon of 3% Hydrogen Peroxide: Mix 1 cup, 9 tablespoons, and 2 teaspoons of 29% HP with 14 cups, 6 tablespoons, and 1 teaspoon of water.


Dilution Table

Dilute 27% Hydrogen Peroxide Down


1 part 27% H2O2 to 1.5 parts water = 10.8% Hydrogen Peroxide

1 part 27% H2O2 to 8 parts water = 3% Hydrogen Peroxide

Dilution Table

Dilute 12% Hydrogen Peroxide Down

1 part 12% H2O2 to 1 part water (12/2) = 6% Hydrogen Peroxide

1 part 12% H2O2 to 3 part water (12/4) = 3% Hydrogen Peroxide

1 part 12% H2O2 to 11 part water (12/12) = 1% Hydrogen Peroxide

Make 1 gallon of 3% Hydrogen Peroxide: Mix 4 cups of 12% HP with 12 cups of water.


Dilution Table

Dilute 10% Hydrogen Peroxide

1 part 10% H2O2 to 0.5 parts water (10/1.5) = 6.6% Hydrogen Peroxide

1 part 10% H2O2 to 2 part water (10/3) = 3.3% Hydrogen Peroxide

1 part 10% H2O2 to 2.5 parts water (10/3.5) = 2.85% Hydrogen Peroxide

How to make a gallon of 3% Hydrogen Peroxide: Mix 4.5 cups of 10% Hydrogen Peroxide with just under 11.5 cups of water.


Dilution Table

Dilute 6% Hydrogen Peroxcide

1 part 6% H2O2 to 1 part water (6/2) = 3% Hydrogen Peroxide

1 part 6% H2O2 to 2 parts water (6/3) = 2% Hydrogen Peroxide

1 part 6% H2O2 to 3 parts water (6/4) = 1.5% Hydrogen Peroxide

1 part 6% H2O2 to 4 parts water (6/5) = 1.2% Hydrogen Peroxide

1 part 6% H2O2 to 5 parts water (6/6) = 1% Hydrogen Peroxide


Dilution Table

Dilute 3% Hydrogen Peroxide (10 Volume)

1 part 3% H2O2 to 1 part water (3/2) – 1.5% Hydrogen Peroxide

1 part 3% H2O2 to 2 parts water (3/3) = 1% Hydrogen Peroxide

1 part 3% H2O2 to 5 parts water (3/6) = 0.5% Hydrogen Peroxide

1 part 3% H2O2 to 14 parts water (3/15) = 0.2% Hydrogen Peroxide

1 part 3% H2O2 to 29 parts water (3/30) = 0.1% Hydrogen Peroxide

1 part 3% H2O2 to 69 parts water (3/70) = 0.04% Hydrogen Peroxide

Non-Toxic Disinfectant for Viruses

In order to kill viruses, the CDC recommends three different options. The least toxic and safest one for most people is hydrogen peroxide at at least 0.5%, left on the surface for one minute. Alcohol is also safe for many people to use. Source

Where to Buy Hydrogen Peroxide During the Pandemic

You can find higher concentrations at hydroponic stores and sometimes at gardening stores and hardware stores.

You may be able to find hydrogen peroxide at 12% on Amazon. If they are not sold out the next place I would look is online hydroponic stores.

You can also find some concentrations at beauty supply stores (usually 12%).

Filed Under: Mold Avoidance Paradigm, Mold-Free Interiors Tagged With: healthy cleaning products, healthy interiors

Get Rid of Mold in Your Car, Including AC System

January 8, 2020 by Corinne 9 Comments

prevent and treat mold in vehicles

This article covers the sources of mold growth in vehicles – AC system, high humidity storage, spills, leaks, and design malfunctions – and how to prevent them.

I go into detail on the four methods used to clean the HVAC system out, as well as methods to clean mold and cross-contamination in the vehicle as a whole.

The AC is usually the most difficult area in the vehicle to manage microbial growth. While there are certain makes and models of vehicles where this is more of an issue, to some degree it’s a problem in all vehicles due to the inherent design of the AC system.

This post contains affiliate links, upon purchase I earn a small commission at no extra cost to you.

Preventing Mold in Vehicles

Preventing Mold in the AC and Heating System (HVAC)

prevent mold in the car's AC system

The fungi and bacteria grow mostly in the evaporator core and immediate surrounds, due to humidity and moisture that forms when AC is in use. Mold can form in the ductwork as well.

To help reduce mold formation in the AC system, run the fan for the last 10 min after using the AC. (Defrost is also AC, so you need to run the fan for 10 minutes after defrost as well). This helps the evaporator dry out.

Using recirculate can worsen the problem in some situations. Bringing in fresh air (if the outdoor air has drier absolute humidity) as opposed to using recirculate can help the evaporator to dry out.

Another thing you can do is to avoid parking in areas where a lot of debris can enter the air intake.

Similarly, when driving through very dusty areas, you are bringing in dust and spores through the air intake. You may want to turn off the HVAC system completely in those conditions.

Maintenence on the vehicle should include changing the cabin air filter as needed (when it’s dirty).

I would include one of the four HVAC cleaning methods below as a preventative (before you start smelling or reacting to mold) if you do use the AC system regularly.

For those Extremely Sensitive to Mold in HVAC – How do you Turn off the AC?

Many folks who are extremely sensitive to mold do not use the AC system in their vehicle at all. If you refrain from using this right from the start with a new car, you will avoid most of the problems here.

If you want to avoid AC use altogether, using just the heating system should be fine. But, keep in mind many new vehicle models have automatic climate control which will use both heating and cooling under many different conditions (not just when defrosting). If you want to turn off the AC, look for a vehicle where this can be done – new cars have a way to disconnect the AC compressor. Ask a mechanic how to do this.

Does the auto setting on cars use AC and how to turn off AC

If you have already used the vehicle’s AC or you bought a used vehicle that has some funk in the HVAC system, then even the heating setting will circulate the fungi and bacteria throughout the vehicle.

Buying a vehicle with heated seats is a good idea in case you become sensitized to the vented HVAC and need to turn it off for a while (and try and clean it). Some very sensitive folks have had to turn it off permanently if they have not had success with the cleaning methods.

One other hack is that you can externally mount the HVAC system to get easy access to the evaporator. This is a very unusual hack. You can find photos of it in the group Mold Avoiders on the Road.

Alternative Ways to Stay Cool in the Car

Cars that Come with Cooling Seats

Some of these built-in systems blow unrefrigerated air through the cushions. And some use refrigerated air that is tied into the main AC systems. The unrefrigerated air system may be safe in terms of mold prevention.

Safer Cooling Seats (or Heating)

You can also add your own cooling and heating seats to avoid the use of your car’s HVAC system.

Cooling seats that you add yourself work simply by adding a fan that blows unconditioned air which helps to cool you down.

Some use fans and those can be affordable. (Though they might be made of vinyl).

The heated seats use coils, just like a heated blanket or heated jacket. Some models do both.

Then there are gel seats, I like the idea of the ones you put in the freezer first, then you bring it out to the car with you. This is a kids version. If you know an adult version let me know, I think it’s a good idea. You will want to dry those off though, when they come out of the freezer they are probably going to condensate.

Cooling Vests

When I used to have severe heat intolerance, I used cooling vests on my body – both active and passive vests work.

The active vests provide more cooling but are more expensive.

They were life-saving for me until I healed from heat intolerance.

Preventing Mold in the Car (as a Whole)

does mold grow in cars just from sitting in humid climates
Many of us stored our vehicles in the humid winters of the Pacific Northwest, to come back to moldy cars

Why Mold Grows Inside Vehicles

There are a few ways your vehicle can become moldy inside on the seats and upholstery. Sometimes just leaving a car to sit in a very humid place for long periods of time can cause mold to start growing on the seats.

More common though, is a spill or window left open that wasn’t dealt with fast enough.

Other sources of water damage are less common:

  • Debris accumulating in the air intake areas and connected drains (keep your air intake area clean, and change the filter). The cowl intake and drain area can collect debris. Those areas are connected to body cavities that can harbor microbial growth. Thus structural mold is possible in a vehicle, though this is less likely than mold growth in the HVAC and inside the vehicle.
  • Rainwater that has gotten into the HVAC ducts and car interior in some past Ford models – causing hidden pooling of water.

Ways to Prevent Mold Growth in Vehicles

Prevention here is key. Once mold is actively growing and has made it through to the foam in the seats, it’s a huge problem that is hard to fix.

When storing your vehicle for long periods of time in a constantly humid climate, it’s best to leave it in a sunny spot and leave it with a dehumidifier. Climate-controlled indoor storage is of course ideal.

Though generally, a vehicle should be able to withstand a good amount of humidity while being stored, really high humidity for long periods has been a problem. I left a truck in 70-95% humidity for a couple of months and came back to mold growth. No known water intrusion.

Many others in the Pacific North West or in semi-tropical and tropical areas have left vehicles sitting to come back to visible mold growing (and not from leaks).

Both active (electricity-powered), and passive dehumidifiers will help. You can also monitor the outdoor humidity.

I would check on the vehicle (or have someone check on it), both to empty the dehumidifiers and possibly to dry the vehicle out actively with heat and airing every few days if necessary.

When you spill something or leave the window open, just do everything you can to dry it out within a day, which includes the above: usually sun and air, or heat and air. Add dehumidification only if it’s going too slowly.

Decon/Clean Mold or Cross-Contamination in a Car

DISCLAIMER: Some of the cleaning methods discussed in this article, which include ozone, chlorine dioxide, hydrogen peroxide, and quaternary ammonia, require knowledge of safety precautions for handling the materials, and executing these methods. Please take full responsibility for your health and wellbeing and make sure you understand the risks, precautions, and procedures – not all of which are explained here in full (please research them before proceeding or consult with an expert). Full disclaimer here.

use a HEPA vacuum to decon mold in a car

If you do have some light surface mold in the car or cross-contamination, I would start with a deep clean.

If you had a big spill that didn’t dry out, or you suspect someone else did in your vehicle, you might want to open the seat covers to check on the foam. Some have zippers. If they don’t you would have to cut them open to check.

Mold in the foam cannot be properly remediated other than with replacement.

Deep Clean your Vehicle

You can remove light surface mold or cross-contamination by steam cleaning or shampooing the seats.

Make sure it is dried out quickly after that. Car detailing shops can do this. Just make sure you know which products they are using, as some might not be acceptable, toxin-wise.

A mechanic I talked to near Vancouver BC, does a shampoo of the seats with high temp extraction, then an enzyme spray on the seats instead of ozone to reduce odors. I use natural enzymes to break down odors.

DIY HEPA Sandwich for a Car

If it’s not so bad as to warrant a steam clean or extractor shampoo, use a HEPA vacuum, which you can do yourself. Vacuum the seats, carpet, and upholstery.

For a vehicle, you want a rather flexible hose. I would use a shop vac. I’ve used one before with the HEPA filter and HEPA filter bags.

You can then wipe down all surfaces with quats or the cleaning product of your choice. A proper “HEPA sandwich” clean would involve another round of vacuuming.

Having your car or truck professionally detailed can help, as they do a very thorough clean, though I haven’t seen them do HEPA vacuuming.

Using Ozone on Cross Contamination

If those methods don’t cut it, and you are still sensing mold in the vehicle, you will want to use the methods below.

Many people do use ozone and it does work, but it leaves behind oxidation, which smells quite terrible.

Depending on how long you ozonated it for, it can take a while to die down.

I don’t agree with some who say that you will damage the wiring easily, you would have to use extremely high levels for a very long time to do damage like that.

Many mold-sensitive folks have ozonated vehicles at very high concentrations for 24 hours, many times. I have done a couple of 24-hour treatments on my truck.

Car dealerships use this all the time as well (but normally in much shorter treatments, like 1 hour). Many people only do 2-hour treatments for mold, which should not cause damage to the plastics, and would only cause minimal oxidation odor after.

There is more info below on pumping ozone through the HVAC. If you don’t need to pump it through the HVAC, just see my general post on ozone and run it inside the vehicle. I use many of the little ones from Amazon (like this one).

Please read through the precautions thoroughly, since ozone is a dangerous gas that can be deadly.

Another oxidization method, though it is a weaker oxidizer than ozone, is to use chlorine dioxide gas. That method is explained below, in its own section.

Other Fogging Methods for Mold

If you have another decon method that has worked well for you in decontaminating your house from mold, it’s likely you can use that here – like thieves oil fogging, Concrobium fogging, or using quats.

Silver Hydrogen Peroxide though, is likely too much oxidation for most vehicles, though it can be used in the empty part of metal cargo vans.

Chlorine Dioxide Gas to Treat Mold

Chlorine Dioxide, like ozone is an oxidizer. Like ozone, there is evidence that it breaks down mold and mycotoxins.

Although it’s weaker than ozone, you should take the same safety precautions outlined here. It is dangerous to breathe in and it’s explosive in certain concentrations.

You may not need to be so far away from it like with high doses of ozone, which is an upside. It’s also cheaper and easier.

Keep it simple and buy the ready-made tablets or packets on Amazon. They are inexpensive and work just as well as mixing it yourself. NosGuard is one brand, Reset is another one.

Read the safety instructions carefully on the product and make sure you understand them. Never use a chlorine dioxide product in occupied spaces.

If you want to make it yourself, please take full responsibility for your safety and wellbeing. Here are the instructions:

How to make chlorine dioxide gas treatment for the home or car: 6.5 oz (roughly 3/4 cup) Oxine plus 3-4 tsp citric acid in glass or heavy plastic container, one for each room. Leave it for 3 hours for a shock treatment or 24 hours for a deep treatment.

You can make a smaller batch for smaller spaces with the same ratio. It takes about a minute for the reaction to take place, the liquid will turn yellow, and for about 3 hours it will release chlorine dioxide as a gas. Take similar precautions as with ozone for airing it out and re-entering.

Four Methods for Cleaning Mold from the AC (HVAC) System of the Car

1. Take it to a Dealership – Have them Clean out the System

Skill Level – Easy. Results – Can work, depending on which methods they use.

how to clean mold out of the AC system of a car

There are a number of different cleaning methods used by automotive repair shops to clean out the AC system. Some use ozone and even run it through the HVAC in the same way as described in the next section on ozone.

There are also treatments that are similar to #4 on this list, introducing a product into the system to clean the evaporator.

One mechanic explains: “one is a mist treatment, using a product which foams up. You drill a hole in the case and then introduce the mist to the evaporator core and let it sit, give it time to work, and then flush it out.” (source).

Some of these might have fragrance of other toxic additives but others would be acceptable for many folks who are sensitive to chemicals.

2. Using Ozone Through the HVAC

Skill Level – Intermediate. Results – works on most mold and bacteria.

how to use ozone to clean out a car or AC system

This is a technique used by some car detailers and dealerships and mold-sensitive folks.

The simplest way to do it is to run an ozone machine in the car while the vehicle is running so that the ozone is pulled in through the air intake. Most people would run this through for a couple of hours. Depending on the amount of ozone and the time you run it for, you may need a window open to provide oxygen.

If you are running the machine in the car I would use a small machine like the ones on Amazon for under 100$.

Instead of running the vehicle, you could alternatively, hook up the battery to a battery charger to run through the HVAC settings that way.

For any serious contamination or if you want to blast this more directly through the HVAC, mold avoiders tend to use an external ozone machine that pumps in the gas, giving the machine full access to oxygen outside. Bioblaster is the most popular one.

If you are in the Facebook group Mold Avoiders, you will be able to see an example of a Bioblaster hooked up right to the air intake here.

That machine is overkill for me. But others may need this. I would have no problem running the smaller ones on Amazon that I have used many times and pumping those through the HVAC system with tubing from the outside.

To get it through all the different parts of the HVAC system, the ozone needs to run through it on all settings (heat, AC, recirculate). Run it through each setting for at least 20 min. The next section explains more about how to access the air intake.

This is tricky because of how far away you need to be from the ozone. Let it air out each time before coming close enough to the vehicle to change the settings. Again, ozone precautions are here.

3. Spray Through the Air Intakes

Skill Level – Beginner to Intermediate. Results – May or may not work.

spray in the air intake to kill mold in a car
The air intake is usually right under the front windshield

In this method, hydrogen peroxide or quats are sprayed through the air intake.

Some very mold-sensitive folks have had success with 10% hydrogen peroxide sprayed into the air intake with these video instructions (not with toxic products like scented Lysol). Seeing the process in a video really helps to make sense of it.  

Spray the hydrogen peroxide through each setting for 3 min. You can use this mister.

You will be using 29, 30 or 35% peroxide (depending on what you can source) and diluting it down to 10% (here is the dilution table). Please research and take full responsibility for handling and spraying this concentration of hydrogen peroxide.

Some people found this worked better with quats (a type of ammonia). This ACDelco product was recommended.

4. Greg Muske’s Quats Cleaning Strategy

Skill Level – Very Advanced. Results – Likely to work if you do it right.

how to clean the evaporator core
From http://biotoxinjourney.com/clean-driving-machine/

Greg Muske from Biotoxin Journey has a detailed and more complex method of accessing the entire HVAC system and runnings quats (i.e. quaternary ammonium) through it.

You need some mechanical expertise for this method as it does involve drilling into specific parts of the system, which differ depending on your make and model.

You need someone who can understand the heater core diagram for your car, which you can look up online. You’re going to locate the evaporator core. Then drench the two cores by running about one gallon of quats solution into 3 access holes. Followed by a water rinse.

Greg also misted quats through the ductwork via the vents and the opening for the cabin filter directly above the blower (after removing the filter), and air inlet holes located under the hood next to the firewall. Unlike when cleaning the cores, this was not rinsed out. It was dried out by running the heater and fan on high.

Greg then cleaned out the rest of the car by using a steam cleaner on the carpet with Thieves Oil Cleaner. (You can use the cleaner of your choice). All other surfaces in the vehicle were wiped down with quats.

Full instructions and a video can be found here: Clean Driving Machine. This section was printed with permission from Greg Muske.

Corinne Segura is a Building Biologist Practitioner with 8 years of experience helping others create healthy homes.

This post was written with input from two engineers, a mechanic, and a car detailer.

Did you find this post helpful? If so you can buy me a coffee to support the research behind this blog. Thank you!

Filed Under: Mold Avoidance Paradigm, Mold-Free Interiors, Tiny Homes and Trailers Tagged With: mold avoidance paradigm, mold prevention, vehicles

How to Size an Air Purifier for Your Home: Calculate the Size of an Air Filter Needed

August 24, 2019 by Corinne 5 Comments

If you are wondering what size or how “strong” of an air purifier you need, these two calculators will help.

To properly size an air purifier or filter for your home or room, the main value you are looking for on an air purifier’s specs is how much air it moves. This will be provided by the company as the CFM (Cubic ft/Minute) value. Think of this as the fan size.

I have two posts on air purifiers – one on PCO types and one on HEPA/Carbon to help you compare models once you have sized them with these charts.

The First Calculator: Calculate What Size Air Purifier you Need 

In the first calculator, you will find out what CFM value you need for your room size.

You need to add your desired or ideal Air Exchange Per Hour (ACH). This is how many times you want the unit to overturn (and filter) the air in the room per hour.

This calculator will tell you what (minimum) CFM value you are looking for and then below is a list of air filters that meet that requirement.

This post contains affiliate links. Upon purchase, I make a small commission at no extra cost to you.

Air Purifier to Choose based on Result of Required CFM from the Calculator

(Note if the required CFM is over 400 you will need more than one unit, I recommend calculating each room at a time, not the whole house).

PCO Models Best for Mold Reduction:

Airocide CFM 14
Molekule CFM 80
GermGuardian AC4825 CFM 125
Vornado PCO375 CFM 145
Vornado PC0575 CFM 184

Here is the Post with Detailed Comparison of These Models

High Carbon (and other Sorbent Material) Best for High Offgassing: 

Amaircare 3000 225 CFM
Austin Air Healthmate Plus CFM 250
EnviroKlenz CFM 250
IQ Air Multigas CFM 300
E.L. Foust 400 Series CFM 380
AllerAir AirMedic Pro 5 Ultra CFM 400
Airpura C600-DLX 440 CFM

Here is the Post with Detailed Comparison of these Models

The Second Calculator: Calculate How Much Air is it Cleaning

Below, the second calculator can tell you how many air exchanges per hour you are getting from an air purifier you already have, or one you are looking to buy, based on the size of your room.

Most experts recommend a minimum of 4 ACH. ASHRAE (The American Society of Heating, Refrigerating and Air-Conditioning Engineers) recommends a minimum of 4 ACH for patient rooms in hospitals, 5 for intensive care units and 25 for operating rooms.

These two calculators helped you find out your ACH to CFM calculation and your CFM to ACH calculation.


Corinne Segura is a Building Biologist with 8 years of experience helping others create healthy homes.

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Did you find this post helpful? If so you can buy me a coffee to support the research behind this blog. Thank you!

Filed Under: Healthy Interiors, Mold-Free Interiors Tagged With: healthy interiors

Using Ozone to Kill and Denature Mold

July 6, 2019 by Corinne 76 Comments

The Effectiveness of Ozone Generators on Mold, Mycotoxins, Fragrance, and Smoke 

Ozone kills and denatures mold on surfaces, and breaks down many VOCs and odors such as perfume. It can also remediate smoke smell in certain materials. 

Ozone has also caused a lot of damage, not just to the breakdown of certain materials in a home, but it seems to exasperate some toxins, causing many people to not be able to return to their house for a long time, or ever.

This post contains affiliate links to relevant products that I use and recommend. Upon purchase, I earn a small commission at no extra cost to you.

Please take full responsibility for your safety when using ozone. Make sure you read and understand all the precautions in this post. Full disclaimer is here.

This post has been reviewed by Tim David, HVAC professional with 30+ years experience.

Does Ozone Denature Mold and Mycotoxins?

[Read more…] about Using Ozone to Kill and Denature Mold

Filed Under: Mold Avoidance Paradigm, Mold-Free Interiors Tagged With: healthy interiors, mold avoidance paradigm, mold prevention

The Best Air Purifiers for Mold – A Review of PCO

January 3, 2019 by Corinne 131 Comments

Updated Winter 2022/2023

PCO Air Purifiers – Which Ones Reduce Mold and Which Ones are a Scam

Photocatalytic oxidation (PCO) is a technology that breaks down mold, VOCs as well as some pathogens.

My interest in these air purifiers comes from first-hand accounts of this benefiting homes with low levels of mold and volatile organic compounds (VOCs), and from the studies showing the eradication of mold and mycotoxins.

I am really excited about this technology as something that can safely break down mycotoxins and odors. Some people may be interested in its effects on breaking down viruses and bacteria as well (including SARS-2).

What is PCO?

In photocatalytic oxidation, UV light hits a catalyst, usually titanium dioxide, creating hydroxyl radicals (OH) and superoxide radical anions (O2–). These molecules bind with and break apart pollutants into harmless molecules.

Best for Mold, Not VOCs

Right from the first version of this article which I published in 2017, I qualified PCO technology as best for mold reduction, not for VOC reduction. I have a different post on the best air purifiers for VOCs.

The reason is that in real-life circumstances the chemical breakdown of VOCs is not a simple linear process. Byproducts like aldehydes can be (and often are) produced as an intermediary product of PCO.

With a high amount of hydroxyl radicals in a closed chamber experiment it will almost certainly break everything down (with enough time) into harmless molecules, but in a home with relatively high VOCs, the results could look different.

Brands Under Fire

It has not surprised me (or really concerned me) that big brands have come under fire for some of their claims. What did shock me when I did the initial research is that smaller air purifier companies get away with outrageously false claims since no regulatory body even has time to get to them.

I would say most companies are exaggerating claims. My focus was on the technology itself, and what studies based on that technology show us, and to remember that there are only a few types of air purifier technologies out there – their claims need to fall into one of a handful of categories.

What About HEPA?

HEPA filters do capture some mold spores and this article does include filters that include both PCO technology and HEPA, though the main focus of this article is on PCO.

If you’re looking at HEPA filters that don’t include PCO, and filters that help with high levels of VOCs, the post on filters for VOCs will be more relevant.

My recommendation is based on the most affordable and effective products that I have found. Upon purchase, I earn a small commission through affiliate links at no extra cost to you.

1. Vornado – The Best of Inexpensive PCO Air Purifier (What I’m Using)

I use the Vornado air purifier. The Vornado PCO375 and PCO575 are the PCO air purifiers with the best value. (At around 350 and 400 dollars, respectively).

They have true HEPA and activated carbon in addition to UV light and titanium dioxide. Most PCO units are much pricier or don’t include all three air purification methods.

Vornado PCO air purifier in black

True HEPA and activated carbon capture dust, pollen, pet dander, smoke, bacteria, mold spores, dust mites, and odors including VOCs.

PCO and carbon are the main technologies used to reduce odors and VOCs. (Ozone can as well, but it is very risky, I have a post all about ozone).

PCO actually breaks down molecules including molds and mycotoxins. I like that it has all three main air purification methods for a good price.

Why I chose this unit:

  • The PCO component has true UV and titanium dioxide
  • Respected brand name
  • Noticeably brings down odors in new apartment and new cargo trailer
  • Has a 10-year warranty
  • Replacement parts are reasonably priced ($25 bulb every year, $35 titanium dioxide screen every 5 years – for the PCO related parts)
  • Does not put out ozone

What I don’t like about it:

What I don’t like about it is that the unit itself offgasses a little bit (I am extremely sensitive). Not everyone thinks so or would notice this. After two weeks I found it to be good. I’m happy with it offgassing within two weeks. (Anyway, all air purifiers offgas a little).

The other drawback is that the amount of titanium dioxide is quite minimal so it may not be producing as many hydroxyl radicals as other PCO units. I am going to go with Molekule if I try another brand of PCO air purifier (more on them below).

A photo from the top looking down on the Vornado air purifier in white with black grills on the top

Model 375 versus 575

The difference between the two sizes is that the PCO575 has a lower low speed and a higher high speed. The PCO575 has 2x the HEPA and 2x the activated carbon of the PCO375.

They both have the same PCO technology – so if you want to increase the effectiveness of the OH molecules in a large space you would want two of the PCO375 instead of one PCO575.

The 375 has a 113 CFM on high, 28 on low.

The 575 moves 156 CFM and is advertised for 258 sq ft., which would get you about 5 ACH in that room.

Buy the Vornado PCO375 and PCO575 from Amazon.

Some other PCO units are more or less the same unit re-branded: Continental Fan CX1000, Catalytic Pure Air, Field Control Trio / Sun Pure SP-20C. They seem to use a very similar PCO catalyst style to the Vornado with a titanium dioxide plated metal screen.

What are Air Exchanges Per Hour (ACH) – Air exchange per hour is how many times you are “replacing” the air in the room per hour, this is a key area of comparison with air purifiers.

ASHRAE (The American Society of Heating, Refrigerating and Air-Conditioning Engineers) recommends a minimum of 4 ACH for patient rooms in hospitals, 5 for intensive care units, and 25 for operating rooms. For the purposes of those extremely sensitive to mold and VOCs, we want about 5-10 air exchanges per hour.

To maximize how much air in the room the air purifier can process, put it in a central location.

How do You Calculate the ACH From a Unit’s Specs – You always want to find the CFM of the unit. The CFM is the capacity of the unit to move air – how much air it moves through the machine. CFM stands for Cubic Feet Per Minute. You need the CFM to calculate ACH. I made two calculators to calculate ACH from CFM and CFM needed from the room size and desired ACH.

2. GermGuardian – The Best Small & Inexpensive Unit

Another brand that is very affordable and also incorporates HEPA, carbon, and PCO is GermGaurdian.

I have heard of people using it in trailers and being happy with it. At $89 it’s a steal. And it has 5.5 ACH in 171 sq ft.

But this is small and simple, I would only use it in tiny spaces if you can’t afford something better/bigger.

Buy the GermGuardian on Amazon.

3. Molekule – Top Overall Pick

If I had to go back and pick one right now, I would choose Molekule.

This is a slightly different technology called PECO. 

Here is a summary of their studies – very promising results on eradicating mold. The data they showed me showed it worked better on mold than PCO.

Their newest filter option also contains HEPA and some carbon.

This company has well-respected big names behind the design. The inventor of Molekule is the person who discovered PCO. He has an impressive resume.

I will be trying this machine out as I think it is very promising.

The warranty started as a 1-year warranty but now it is a 2-year limited warranty. The company has been around since 2016.

Molekule Air Pro

The Pro is the biggest model, it’s is advertised as cleaning up to 1000 sq ft. You will get 1 ACH in a room of 1000 sq ft with 8.5 ft ceilings.

It goes for $1,199.

The Molekule Pro does come with a basic particulate filter but that is not the primary function of this unit. That is likely to keep the other filters and components free of dust. If you want to add more particulate filtration they do now offer a HEPA filter for the Pro.

The replacement filters for the Pro are $150 which lasts about 6 months, so replacement filter costs are high.

Molekule Air

This is their original model. They state it cleans up to 600 sq ft. You get 1 ACH in a room of 600 sq ft with 8.5 ft ceilings.

It goes for $998.

The replacement filters are about $200 per year.

Molekule Mini

The new Molekule Mini provides 1 air exchange per hour in 250 sq feet. They offer a HEPA filter option for the Mini.

It sells for $499.

Which Size Should You Choose?

In a room that is 15 by 15, the biggest model would get you 4 ACH. That is a good number of air exchanges to aim for if you want a high level of air purification.

Here is my calculator that helps you size an air purifier for your room based on how many times you want to overturn the air in an hour.

If you can afford it, and if design is important to you, Molekule with HEPA is my top pick. 

Buy from the Molekule website or Amazon.

Other Contenders

1. Air Oasis – A Review

The Air Oasis Ionic Air

The Ionic Air has three components, one, a PCO component – germicidal UV light and a catalyst that is made of different metals to produce hydroxyl radicals; two, a bi-polar ionizer; and three it produces ozone (either through the UV light or via the ionizer).

The 3000G3 model is rated for 3,000 sq ft and only moves 11 CFM of air. 3,000 sq ft at 11 CFM is 0.02 air exchanges an hour. That is very little air movement. (I am using 8 ft ceilings in my calculations of CFM to ACH). But that’s not important for the ionizer and ozone components.

Technology – PCO

The company states that the PCO process creates “ionized hydroperoxides”. I have seen other PCO air purifier companies make this claim. This seems to me a confusing way to describe PCO which primarily produces hydroxyl radicals and secondarily produces superoxide radical anions (O2–).

Whenever I’m reviewing an air purifier I always keep in mind that there are only a small handful of possible technologies they can use. When it sounds like they have invented something new it means it’s time to look into their claims and see which of the few main technologies they are really using.

Technology – Biopolar Ionzation

A bipolar ionizer produces negative and positively charged ions that can cling to pollutants, dropping them to the ground where they can be cleaned and they might be able to break apart (chemically) some types of pollutants or biologicals. This type of ionizer can sometimes be advertised as cold plasma ionization (source).

Technology – Ozone

The air purifier also relies on low levels of ozone for air cleaning technology. You can have one made without the ozone production component but that seems to be a key component of its air cleaning abilities.

I personally do not consider any level of ozone, unless it is minuscule, to be safe to use in occupied spaces.

Final Thoughts on Air Oasis Ionic Air

I know this brand because mold doctors promote it. I was surprised when I dug into it to see how little air moves air through it, and that it gives off ozone. It was not approved by CARB at the time of writing the original version of this article (2017). It is now meeting California levels of safe ozone (CARB). (Though the upper limits of ozone in CARB are too high for me, personally).

Since the time I first wrote this article, it seems the company is much more clear that this is an ionizer. How much air it moves is not that central to an ionizer (but is for the PCO component). I’m a little wary of bipolar ionization which Dr. Marwa Zaatari, Mechanical Engineer, claims is not necessarily effective.

It has a 3-year warranty and the replacement parts are $80 every 2 years.

Air Oasis iAdaptAir

The newer iAdaptAir is similar but claims to produce zero ppm of ozone. This is something I would be more likely to try.

It contains a HEPA filter, a carbon filter, PCO technology, and a bipolar ionizer.

Most ionizers give off ozone but it is possible to produce ions with minuscule ozone that does not register against background levels.

It comes in three different sizes for $399, $599, and $799.

The small, covers 250 sq ft and has a CFM of 58 (2 ACH per hour), the medium, covers 550 sq ft with 151 CFM (2 ACH per hour), and the large covers 850 sq ft with 237 CFM (2 ACH per hour).

This is really a great little unit if you want HEPA, carbon, PCO and you want (or don’t mind) the ionizer.

Air Oasis Versus Molekule – A Comparison

I personally would not use the Air Oasis Ionic Air with ozone so I will compare Molekule to the ozone-free iAdaptAir.

The main comparison that I can’t quantify is the strength of the PCO component – just how many hydroxyl radicals do they produce. Molekule has a good reputation for working well even before the HEPA option was added.

On the other hand, iAdaptAir has a really good value for what it provides. The only downside for me is I’m not a big fan of bipolar ionization as I have my doubts about its effectiveness and I tend to be sensitive to ionizers.

Both are good choices, however.

Here’s the comparison:

Molekule Air

  • Modified PCO technology
  • HEPA filter is optional
  • No ozone
  • CFM ~80
  • Costs $998
  • Replacement filters $200 per year
a black and white button that says buy that you can click on

iAdapAir Medium

  • Modified PCO technology
  • True HEPA filtration for particulates
  • Some carbon for absorbtion of VOCs
  • Bipolar ionizer
  • No ozone
  • CFM 151
  • Costs $599
  • Replacement filters $100 per year
a black and white button that says buy that you can click on

2. Airocide Air Purifier Review

Another popular PCO machine that has been around for a while is Airocide. The APS 300 has a CFM of 40.

I like that the website has studies confirming that it doesn’t give off ozone. They used to have a short case study on breaking down mycotoxins when this article was first published in 2017 (though I can no longer locate it at the end of 2021).

It looks cool which is a plus.

The claims about removing dust, dust mites, and allergens do not seem all that accurate (especially after seeing what Molekule just went through with the FDA suit) since PCO machines do not filter particulate pollutants (according to the EPA).

It had a 5-year warranty when I first wrote this article, now it is a 2-year warranty. It costs $100 a year in replacement parts.

Why did I rule it out for myself: Most of the PCO machines do not include HEPA and activated carbon like the Vornado. This is a lot more expensive than Vornado or Molekule, but doesn’t move as much air.

3. What I Would Not Go With….

This is an air purifier that I myself would not consider. You can skip this section unless you want to hear all the details about HiTech.

HiTech Air Solutions Review – Is it a Scam?

HiTech Air Solutions, a brand known among some mold avoiders, makes Air Reactors that claim to be PCO machines.

To start, the 101 model ($2000) is very expensive relative to the other PCO machines. From looking at the inside of the machine they use basic components that total under $150 for all visible parts if I bought them: four foam/coarse dust filters, two UVC lights, two computer fans, and a 4U 19″ rack case.

The claim here is that some of these filters are photocatalysts that produce OH molecules – that there is something invisible called “Technosite®” (no evidence of this trademark with USPTO) impregnated onto the filters. They may be using a clear titanium dioxide catalyst on the polyester filters.

I have also seen two other odd claims from sales reps of the company – one, that the filters are coated with Sporax (I have seen pictures of their filters with Sporax, though they later denied this.) And that both the filters and the bulbs are also coated with something proprietary – both things that I would want to know are safe to use with UVC light.

HiTech makes some pretty astonishing claims that have not been backed up by evidence. Also feel free to ask a chemist how this is even possible:

They claim their OH molecules (which are produced by the PCO process) last much longer in the air than the other air purifiers’ OH molecules (~6 weeks instead of ~15 seconds) based on “a study by Texas Tech”, though this study cannot be produced by the company. Dozens of phone calls were made to track down the existence of this study and nothing turned up. Even more, the University claims it does not conduct studies give the results on the phone, and then withhold the report for large sums of money (as the reps claim).

I have not found any evidence that this “study” exists or ever existed, or that this produces a totally different kind of OH molecule. Just ask a chemist how you can have a stable but also reactive OH molecule.

I would like the company to disclose what they are using in this machine so we can know if it is safe and effective, or, provide studies that exist that show which molecules and byproducts this machine produces.

The burning smell is worrisome to me. I have seen photos of users’ machines showing the filters having been burned through by the UV light. That will produce offgassing. The accounts I have seen of bad reactions are also worrisome.

HiTech claims it produces 99.9% pure air. I have seen no studies to back up this very broad claim. What is the level of contamination in the air to start, and what is “pure air”? Also note, PCO technology does not filter particulate pollutants (EPA).

I have contacted a technical rep, sales rep, and the owner for these studies – they responded but were not able to provide them. Others have contacted them as well for this information.

Their bigger units are ~$5000 and ~$6000 dollars!

The HiTech sales reps make 25% commission off each unit (at the time of writing in 2017) and they usually recommend multiple units for houses. The commission for the three sizes is roughly: $500, $1000, and $1500! The cost of the replacement parts are $140, $190, and $295 per year, for the three different sized units.

HiTech has not submitted their Air Reactors to CARB at the time of writing in 2017, to confirm they give off a safe level of ozone. However, the bulbs they are using are USHIO brand UV bulbs with a 2G11 / PL-L base which do not give off ozone. They use another brand as well, LSE Lighting UV bulbs, with the same base. From what I can tell this bulb would not be any different from the USHIO brand.

FDA Approval of PCO Machines

The FDA approvals I have found are one for a PCO machine involving titanium dioxide (it proved to destroy some bacteria, viruses, and mold) for specific commercial uses.

The Airocide, Odorox, and Molekule Air Pro all have FDA approval as type 2 medical devices for use in hospitals. The first two use titanium dioxide and UV technology.

The FDA approval cannot be stretched to make safety or health claims on any device that deviates from this technology or has unknown additional technologies.

HiTech claims to be FDA approved, I can find no evidence of that. Anyone can search for FDA approvals here.

Adverse Reactions to PCO Hydroxyl Generators

I have heard of people having bad reactions to HiTech. I have heard only one bad reaction to Airocide, and a couple of bad reactions to AirOasis both the ozone and non-ozone types.

I do not know what accounts for these bad reactions. It does not appear that there is an ozone issue (apart from AirOasis). Dr. Daniel Cagua Koo has also noted that some patients simply don’t do well around this technology.

Since writing I have heard of some bad reactions to Molekule with about 50% of sensitive folks buying it being happy with it, and the other half not, and one bad reaction to Germ Guardian.

It is possible that PCO is creating harmful byproducts in high VOC buildings.

If you are in high VOCs I would focus on a filter that has a lot of carbon – like these I review here.

My interest here is for a house with extremely low VOC levels and already extremely low levels of mold. And the hope here is to keep the air as low in mold as possible.

I would love to hear from more people who have tried these other brands. Let me know if you have had good results or a bad reaction to a PCO machine.

Do PCO Machines Give off a Burning Smell

According to Airocide, the UV bulbs themselves emit a bit of a burning smell at first. They burn theirs in for two days, but sensitive people can smell it for up to a week.

The Vornado PCO had a very slight burnt smell at first which seemed like the smell of carbon.

HiTech states that the burning smell is mold/mycotoxins breaking down. I see no evidence for this claim.

Airocide made a statement that mold does not produce a smell when broken down by OH molecules.

A HiTech user also stated that the UV lights have burnt right through the “reactor pads”. This is consistent with a theory that the UVC lights are burning the “reactor pads” and causing a smell.

Corinne Segura is a Building Biologist Practitioner with 8 years of experience helping others create healthy homes.

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This post was written with the technical assistance of an electrical engineer, though the opinions and conclusions are my own.

Filed Under: Healthy Interiors, Mold-Free Interiors Tagged With: mold avoidance paradigm, mold prevention

Composting Toilets for Those Sensitive to Mold and Chemicals

September 18, 2018 by Corinne 4 Comments

I want to talk about composting toilets and greywater systems from the standpoint of the chemicals involved, how likely they are to grow mold, the costs, and the benefits for someone with MCS to being semi (or totally) off the grid.

This post contains affiliate links on some of the products I use and recommend. Upon purchase, I earn a small commission at no extra cost to you.

1. First Generation Composting Toilets

I had the SunMar Spacesaver in my tiny house because it’s the smallest indoor self-contained composting toilet I could find at the time of building in my area, and the only one that would fit in my tiny bathroom.

It was also the best-priced unit at the time. I absolutely do not recommend this toilet as it completely fails at handling liquids. Here are a few of the other challenges followed by some recommended brands.

Toxic Additives in Composting Toilets?

I had a bad chemical reaction to the additives. I didn’t know that the toilet requires a significant amount of input in terms of additives (and money).

There are three things you need to add regularly: 1) an enzyme spray which smelled fine to me, like a very light non-toxic soap might smell, 2) a bulking material of hemp, peat moss…. and maybe sawdust. This material could be problematic for those extremely sensitive to mold.

You could definitely make/source your own bulking material to make sure it’s safe for you.

And 3) the microbes that you add to speed up the compost and keep it “odorless”.

I had such an acute reaction to the microbe mix. It smells somewhat like a urinal cake. Everything online said it was non-toxic and natural… hmm. I called them to ask what is in it and they said citronella.

Citronella contains methyl eugenol which repels bugs and is a possible health concern needing more studies to confirm its safety. There are a few essential oils I consider to be harmful for MCSers and citronella is definitely one of them.

I had to figure out what kinds of microbes were needed for the toilet and I found out that EMBokashi will work just as well and doesn’t have fragrance added.

After using the toilet for a few months, I can say that the enzyme spray is not necessary. You could just use the Bokashi or Bokashi and a bulking material.

However, I am not happy with this model at all. The upkeep is very smelly work and it often overflows with only one person using it.

Dealing with the overflow is horrible. Even before it overflows the system is such that liquid accumulates below the tray where it becomes very smelly, and moldy.

One person using this toilet full time requires that it overflows into a septic system or blackwater system. Not very self-contained at all.

Offgassing the Unit

Another chemical issue is with the unit itself. It needed some offgassing outside to get rid of the plastic and glue smells. I left it outside for a week. A month would have been ideal. I was extremely sensitive at that time.

Necessary Hook-Ups for the Compost Toilet

There is some installation necessary that ideally would be contemplated before building the bathroom of a new house!

A vent has to go through the wall, outside, and above the roofline. An emergency overflow valve needs to go through the floor and out to…. somewhere (a bucket)… or to the septic or sewage drain if you are on the grid.

You do not need to have water as an input for this type of unit or bolt it down in any way.

There are electric and non-electric self-contained units. The Spacesaver is electric. It does have a small fan which creates negative pressure, though it can easily be overpowered by a bath fan – pulling the odors back out.

There is a need for a special outdoor compost for self-contained indoor composting toilets; they say the humus the toilets produce is totally benign but there is no way it is in there long enough to be benign.

Benefits of Having a Composting Toilet

There is a huge benefit to being off the septic system and that is the freedom to put your tiny house/yurt/dome on any piece of land with some extra amps to spare & a freshwater hose (and of course you could get totally off the grid with solar panels and rainwater collection).

Challenges of Having a Composting Toilet

If you are comparing the initial cost and cost of (ongoing) inputs to just hooking up to a city sewage line, then the self-contained composting toilets are going to seem expensive.

If you are comparing the cost to installing a rural septic tank and the maintenance of that septic tank, then it starts to seem like a really good deal.

If you are extremely sensitive you’re going to want to make sure you can source some tolerable bulking material before you start.

A lot of the maintenance also includes some strong smells of excrement so you have to be able to tolerate that. It you don’t want things to start festering and producing bacteria and mold you have to empty this often, possibly every day.

I have seen some mold growing in the finishing drawer.

Another challenge for people who are disabled is that there is some work – there is the buying of the additives and maintenance. Maintenance involves turning a crank every second day for a minute.

Unclogging the mesh screen if that ever clogs up, checking to see if the system has overloaded via the emergency drain and other troubleshooting if anything goes wrong.

There is a fair amount of troubleshooting so far for me. The fan will have to be replaced or fixed if and when it stops working.

You also empty out the bottom drawer of humus every few weeks.

I’m having trouble with the Spacesaver as I don’t think it has enough capacity for one person let alone two. The tray is filling up too fast, which can be a major problem if you don’t have somewhere safe to dump it and it overflows liquids.

I don’t recommend this one as it does not handle liquids well. A urine separator would be the next type to consider.

2. Urine Separating Composting Toilets

Those who live in tiny houses began switching over to urine seperator toilets to get around the problem of the first generation of composting toilets.

Nature’s Head  and the Separett are well liked.

What’s different about these is they separate the urine out to a separate collector.

This is crucial. It is the reason the Sunmar was overflowing and going moldy in the tray for me. I would go with one of these for sure when I replace the Sunmar.

3. Dry Flush Composting Toilets

The other type that is popular now and is even more suitable for the chemically sensitive is the dry flush self-contained.

A dry flush self-contained uses bags to contain the human waste. It’s much cleaner and much easier.

The bags are somewhat expensive and you have to carry them out to a trash bin.

Some people are really happy with this and it eliminates a lot of problems with smells and mold with the other ones.

4. Incinerating Toilets

Incinerating toilets like the Cinderella are making a bit of a comeback. Some chemically sensitive folks have chosen this option for ease of use.

No human waste to collect, no bags to throw out.

Folks who are chemically sensitive can often tolerate the smoke but you will have to decide if that is right for you.

Those primarily mold sensitive may like this option.

5. Bucket and Bag Set up

If you live in a simple trailer or van or are camping you may want an even simpler toilet that uses bags. The Cleanwaste one is popular. And I have tried the luggable loo with success.

Other Types of Composting Toilets

This post deals with indoor self-contained units but other types of composting toilets include: an outdoor bucket system, an outdoor dug out (outhouse), indoor central flush, central dry, and indoor bucket systems. 

6. Greywater Recycling

Being off the septic system means you also need to safely recycle your greywater – which is the water that comes out of the kitchen sink, bathroom sink and shower.

These contain more bacteria than you think via raw meat and the bacteria on your body etc.

Eco-Sense has a really good free overview and guide including using a worm bin system to remove food scraps from the water. Here are the instructions for the worm bin filter system.

There are a lot of different types of systems and for more detailed instruction this book is super user-friendly and outlines the simplest options depending on the number of people you have on the system.

You need both some kind of filter and water dispersion. We tried just burying the pipe so that the water would simply drain into the ground but the water could not absorb fast enough and it backed up through the house. Gross, yes.

We dug a small pit and it still backed up. Right now I have a larger pit but it still has no filter on it, it worked fine for years with little upkeep. (Note it’s not technically safe to have the water drain above ground, but this did work fine for me).

Corinne Segura is a Building Biologist Practitioner with 8 years of experience helping others create healthy homes.

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Filed Under: Healthy Building, Mold-Free Interiors, Tiny Homes and Trailers Tagged With: healthy interiors, tiny homes and trailers

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Hi, I’m Corinne Segura, I hold a certificate in Building Biology, and a certificate in Healthier Materials and Sustainable Buildings, among other credentials below. I have 8 years of experience helping people create healthy homes.

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