The best solution to indoor air contaminants is dilution, by a long shot.
This solution works much better than air purifiers.
An energy recovery ventilator (ERV) or heat recovery ventilator (HRV) can be used to overturn a lot of air and drastically reduce the indoor pollution levels.
You should find out which is better for your climate, but ERV will work for most people.
This article shows my set up of this ERV in a portable way (you could do this in a window).
Please note I’m not making a call on whether this will be allowed by your landlord or codes, that part is up to you.
Expert Review: This article was reviewed by Luke Skaff, Electrical Engineer
This article contains affiliate links, upon purchase I earn a commission at no extra cost to you.
Air Exchange
This is far better than just opening a window and running your exhaust fans because it brings in air that is closer to the indoor temp and humidity than the outdoor temperature.
I had an HVAC expert do the calculations on what temperature and humidity level the incoming air would be through this ERV in a cold winter and in a hot humid summer (you can see that here).
I talk about my personal experience with this Panasonic unit more on Substack.
The Panasonic WhisperComfort
Panasonic WhisperComfort Energy Recovery Ventilator (ERV) is a stand-alone air exchanger that provides balanced ventilation.
WhisperComfort ERV is listed for ceiling or wall mount applications.
So if you own a home or have permission to install this in a ceiling or wall it will provide you with lots of air turnover.
If you don’t own the home and want to install this in a window this article will explain how to do that.
How to Set up The ERV in a Window
Now this photo obviously isn’t using a window but the setup will be the same – there are just a few modifications to make this work better in a window.
I outline how to set this unit up in a window in Substack, as well as some alternative ERVs that would be easier to set up in a window than this.
Other Things to Note:
1. The extremely sensitive may need to off-gas the ERV first by running it for a while before using it, as all new appliances have some plastic odors.
2. This brings in a LOT of air from outside. You will definitely get dilution, but this may be too much air in a very small trailer or a very small bedroom.
3. The air it brings in will not be as warm or as cool as your indoor air, nor as warm or cool as your outdoor air, but it does help mediate the temperate (and humidity).
Another way to do it – There are other ERVs that are made for windows or are easier to modify for a window installation, I go through them here on Substack.
Corinne Segura is an InterNACHI-certified Healthy Homes Inspector with certifications in Building Biology, Healthier Materials and Sustainable Buildings, and more. She has 10 years of experience helping others create healthy homes. You can book a consult here.
Join the top Substack on healing from MCS and mold!
Christine
My partner and I bought and installed this ERV according to the instructions here and the thing seems to do practically nothing. Our goal was to lower CO2 in our 12×14 bedroom while we sleep and the ventilator does less than leaving a small window open (which we can’t continue to do when we need to run our AC or it’s freezing cold outside). I would have expected something touted as moving so much air would be much more effective and as it is this was a waste of hundreds of dollars.
Corinne Segura, Building Biologist
this ERV in the post moves a tonne of air, too much for a small space even to be comfortable, this was something i used. if it’s not moving air then it’s either defective or not set up right
Yoko
Has anyone tried attaching carbon filter to filter VOC/gas/smoke from outside?
Corinne Segura, Building Biologist
Luke Skaff looked at the motor and said with this one it will bias the air flow and create negative prssure but there are some that will be able to balance the air flow with a filter on the intake
Art
Great ideas here. Most grades of Filtrete electrostatic furnace filters will exhibit ultra-low pressure drop at the modest face velocities associated with a mere 10, 20 or 30 CFM. The Filtrete filters are sold in a conventional 12X20X1 size that are used in HVAC filter boxes for use with 4″ duct, such as the Fantech 6″ FB-6 or the Aitecac 4″ filter box . It would be easy to place one of those filter boxes inline in the intake airstream; swap out its generic filter for a Filtrete (in the 1000 to 1900 rating range; and measure the pressure drop created. From existing data your engineer is probably going to detect only a fraction of 1 mmH2O of pressure drop at 30 CFM (remembering that the pleats greatly increase the nominal 12X20 surface area). If such a tiny amount of airflow resistance is enough to throw the Panasonic out of balance, there’s something wrong with the Panasonic’s design, because we are talking about amounts of airflow resistance that are well within the range that may be encountered by such a device anyway, due to wind or building pressurization. Ask your engineer to test my predictions, but caution him that most HVAC manometers aren’t precise enough to accurately measure such tiny amounts of airflow resistance. It usually requires a calibrated micromanometer. Of course, the filter will need to be changed to maintain the lowest airflow resistance.
But if he doesn’t like even such an ultra-low-resistance filter on the intake side only, ask him about putting filter-boxes on BOTH airstreams (intake and exhaust), to maintain very similar resistances.
Celeste
Hi Corrine and Luke,
I’m looking to rent a house, but can smell the previous tenants either smoked inside or smoke blew in from the outside and I smell some residue. What is the difference between using our portable A/C Units (that has two tubes-one for incoming air and there other for out going air vs ERV Air Exchangers? I appreciate it!
Corinne Segura, Building Biologist
Luke says a portable AC with two hoses is not bringing in outdoor air into the home, the intake hose air goes into a sealed compartment where the condenser coil is. Not perfectly sealed but it’s not bringing in a tonne of outdoor air like an ERV is.
sharon o'sullivan
Hi
I am beyond sensitive house bound but as the summer comes it is to hot not to open window. If the pollen comes in it makes my unbearable condition even worse, daily the burning in my face is like acid being poured over I have to sit by a plug in filtration system but this is not helping with pollen my pain gets even worse I have to sit all day with ice packs on my face until I go to bed. I get thousands of blisters on my face and my whole body is itching and crawling. I am looking for air conditioning unit will an EVR unit help with this also will it make the inside cooler. As the air outside will be worse than inside will this work at all. Mind you probably can’t get then in the UK anyway.
Thank you, you really are a life saver
Sharon
Corinne Segura, Building Biologist
an ERV wont make it cooler but you can get a window AC unit or a portable unit with double hose
Joe
How is 30CFM of outdoor air better at reducing indoor pollutants than say, 80 CFM Clean Air Delivery Rate from an air purifier?
The air purifier is much less expensive, costing $100-$200, smaller and is portable to boot.
Jonathan
Having both is even better.
The ERV will help get CO2 out of your living space by exchanging the used air with fresh outside air. This can help with particulate and smells, but only in the same way an open window can. What the ERV gets you vs an open window is much less loss of heating or cooling in your interior air. Fresh air without increasing your heating or cooling costs much.
Air filters are very useful for reducing particulate (pollen, dust, viruses, bacteria, mold), and if your purifier has activated charcoal, it can help with Volatile Organic Compounds (VOC) and smells. But the air purifier can’t do anything about CO2, which can build up quickly in poorly ventilated spaces.
Corinne Segura, Building Biologist
You can try it for yourself but an air purifier is never as effective at reducing pollutants than air exchange assuming the outdoor air is good.
Alex
Hi Corinne,
Do you know if this or any other ERV units can be programmed for unbalanced ventilation, so that I could keep my living space under slight positive pressure at all times? Thanks so much for all that you do!
Alex
Corinne Segura
not this one, but Broan AI yes
Anthony douglas
Hey guys, I’ve started an initiative to try to make a window mount energy recovery ventilator using essentially artisanal/prototyping techniques combined with standard parts. Price quite similar to the rig above, but more air flow and higher efficiency in general. Please see the web page at http://www.openerv.ca, we discuss the issue primarily on twitter, links on the page.
Brigid
Hi Corrine.
We live near some avocado orchards that get sprayed 2-3 a year via helicopter. However. we also have a nice seabreeze as the ocean is about 20 miles away and we happily live in a wind corridor.
Would an ERV be a good idea if I turned it off for a week after the orchard sprays? And perhaps at certain times of the year with agricultural sporing?
Or is it too risky?
Thank you!
You are a Godsend to so many!
Corinne Segura
yes i think that would be fine but if your outside air is always worse than your inside air it’s not a good place to live.
David
Hi,
I’ve been looking for something like this for my small tenement apartment. Do you know what the filters are rated for (merv 6, 7, etc.)