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 is about how to install an ERV in a portable way – 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 make a small 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. This also brings in quite a lot of air, it is variable speed and can bring in 30, 20, or 10 CFM (cubic feet per minute). In a small space that is a lot!
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.
Now this photo obviously isn’t using a window but the setup will be the same.
How to Set up The ERV in a Window
Step One
I mounted the WhisperComfort on a kitchen cart, the type that comes on wheels (kind of like this). I drilled two holes in the wood top layer of the kitchen cart for the ducts to go through. The cart should be higher than the window so that the ducts can run under it.
Step Two
I bought 4-inch metal flex duct and attached them to the intake and exhaust with tape.
Step Three
In my case, I drilled holes in the trailer wall but you will want to exhaust those out of a window. So your window needs to open 4 inches, ideally horizontally but vertically can work too.
For a window, you can buy a hard plastic air conditioner window kit like this (pictured left). (Your window would have to open around 6 inches for this).
Or you could buy the more flexible option. This is a TU fabric window kit (pictured left). And that might be easier to adjust to the 4-inch ducts.
However this only comes with one hole, you would have to cut a second hole and then seal that up with lots of tape.
Step Four
Have an electrician set up the wiring so that you can plug in the ERV. Make sure it’s long enough to reach the nearest outlet. (Normally this is hardwired in, so it doesn’t come with a regular plug to plug it into an outlet).
Other Things to Note:
1. The extremely sensitive may need to offgas 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. You could run it on a timer that connects to an outlet to pulse it or run it on a programmable timer outlet that is based on temperature.
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).
4. This will only work if your outdoor air is clean and better than your indoor air.
Corinne Segura holds certificates in Building Biology, Healthier Materials and Sustainable Buildings, and more. She has 10 years of experience helping others create healthy homes.
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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.)