A New Product You Should Know About: SWERV
Are you a renter, or owner of a studio or small home? Do you suffer from stale air or even mold when the home has to be closed up due to extreme temperatures or air quality issues outdoors? You could benefit from a new product, SWERV.
SWERV is short for “Smart Window Energy Recovery Ventilator”. Energy Recovery Ventilators (ERVs) are normally permanently installed in homes to bring in fresh air from outside, filter it, and heat or cool it by passing it through a heat exchanger. The heat exchanger uses the air that is already in the home to provide the heat or cool to the fresh air. Thus, the only energy used to bring this fresh air in and “condition” it are two small fans–one to pull in air from outside, and one to push air from the room through the heat exchanger. You can read more about ERVs in our article.
SWERV is novel, however, in that it is not permanently installed. The unit can be temporarily installed in a vertical or horizontal slider window by one person, making it perfect for renters, because they can remove the unit and take it to their next apartment. It’s also a step up from simple window fans, because it filters and heats or cools this outside air. There is nothing on the market right now (November 2025) like it.
SWERV uses sensors to detect indoor and outdoor air temperature and humidity, and possibly air quality. Although the website does not say too much about the sensors, the unit “alternates between supplying and exhausting to bring in fresh filtered air, push out stale air, and retain ~80% of the heat and moisture from outgoing air stream.”
The only problem with pushing air into and pulling air out of a room is that it will alternatively create positive pressure and negative pressure in the room. Most apartments are quite leaky anyway (because exhaust fans are normally piped into common ducts between the apartments), so this is not normally a problem. However, if you have neighbors that generate bad or dangerous odors like smoke, during the cycle that pulls stale air out of your space, it could indirectly pull their smoke into your space. A traditional ERV is “balanced” in that it brings in the same amount of air that it’s exhausting from the space, creating no positive or negative pressure indoors. The Swerv saves cost on using a single stream, however, and does not balance ventilation. In this case, it would probably be better to constantly be pulling air in, to create a positive pressure inside and avoid the problems of negative air pressure.
Another plus of this little unit is that it can remove moisture from the indoor air if the outdoor air is cooler. Although again there are no details on this process, if the outdoor air is below the dewpoint of the indoor air, water vapor will condense on the heat exchanger, which can be drained away (similar to an air conditioner that removes humidity through condensation on the evaporator). This can reduce the possibility of mold occurring in your space. This could remove moisture from warm air inside when there’s cold air outside, and it could also remove moisture from warm air coming in when it’s cooler inside. However, it wouldn’t work as well as a dehumidifier during summer as during winter (the airstream being dehumidified in that season is the outside air coming in, which is small compared to the air in the room).
Although SWERV takes up a little window space, it seems like a really useful unit and if there’s only one window in your room, could even be stacked on top of a (well-secured) air conditioner so that both units could be used in the one window. After all, most window air conditioners are not capable of filtering and conditioning outside air to provide good ventilation; they simply have a small vent to let in outside air. Since studies show that sleep is disturbed with higher levels of CO2 in the bedroom and a negative relationship between exposures to air pollution and sleep health, this unit could improve your health by just placing it in your bedroom window and using it while you sleep.
SWERV is in Beta test mode right now and will be shipping its first units in January 2026, through April 2026. Check out their website to learn more and sign up to be a “Beta tester” (Beta testers buy a Swerv and agree to track air quality, temperature and humidity with a sensor, and provide this data as well as any feedback. We’re hoping that this product does well; it seems to fill the niche of providing clean, conditioned ventilation air to smaller spaces in a convenient way!
Photo: SWERVair.com
