I just installed an ERV (Energy Recovery Vent) into my 1970-built bedroom — it has drastically increased the air quality (I have it set to exchange the entire house volume 8x per day). It is as quiet as the ceiling fan, nowhere near as loud as a dehumidifier (which pair well, together, for overall room/house comfort). I also leave the central HVAC fan `ON` 24/7.
There is a HVAC cost because the ERV is only ~60-75% efficient (at recovering heat/humidity with external supply air exchange), depending on the cfm/setting... but it gets rid of every stink, and you smell the morning dew and approaching thunderstorms. As is recommended, I leave mine on 24/7 — it has a boost mode which can be activated with switches wired anywhere else (e.g. bathroom, for during showers)... I plan to use a wallswitch timer for this temporary airflow increase, because the 24/7 setting I've set is 70% efficient, and at MAX it drops to only 60% energy recover.
The Panasonic unit I installed was ~$600, plus an additional $100 in venting. Took me about eight hours to DIY install (but I have decades of blue collar electric under my belt and am familiar with house). This would have probably been bid out ~$2500 if a company were doing it, on a simple install (i.e. <25ft ducting to non-roof penetration).
I think either DIY or Pro expense would be worth it, particularly if your air is stale / litter box / subtropical humidity. Modern building codes require HRVs/ERVs in most new construction, so if your building is even just a couple decades older, ERVs are worth looking in to (HRV if you live in desert climates).
An ERV itself does nothing for air quality, yours is likely just a a fixed plate air-to-air heat exchanger, much easier for a homeowner to maintain than an enthalpy wheel that has a motor and needs additional air filters since the fixed plate ERV has no moving parts.
Setting your furnace fan to ON to increase the number of air exchanges in your house without the heat exchanger would do the same thing.
Your indoor air quality, assuming your HVAC is properly balanced to have positive pressure, is determined by your furnace filter type and age and how clean your ducts are.
There are other types of heat exchangers used to capture heat from exhaust air streams (enthalpy wheels are common in commercial HVAC) but none of them change air quality.
That being said, ERVs/HRVs are amazing and should be in every house, along with domestic hot water recirculating pumps[0] :)
There are also heat exchangers that capture latent heat from your shower water [1] to preheat the cold water line going into the hot water heater, though I am unsure if you’d ever capture enough latent heat back to pay for it. They’re made out of copper so they’re a bit pricey, and virtually everyone has a natural gas water heater where I live (MN), so it’s practically free to heat water.
I disagree — it is literally exchanging outdoor air with indoor air; so perhaps if it was heavily polluted outdoors then it could certainly worsen indoor air quality.
>Setting your furnace fan to ON to increase the number of air exchanges in your house without the heat exchanger would do the same thing.
I think you are misunderstanding how an ERV is plumbed. Unlike furnace `ON` cycling indoor air indoors, the ERV is literally exchanging inside/outside air constantly & entirely, directly through the plate membrane.
>Your indoor air quality, assuming your HVAC is properly balanced to have positive pressure
In the ERV setup I described installing, earlier, it is the ERV which generates/maintains the positive pressure differential.
>There are also heat exchangers that capture latent heat from your shower water [1] to preheat the cold water line going into the hot water heater, though I am unsure if you’d ever capture enough latent heat back to pay for it.
This is why instead of drain heat capture (not economical at microscale) to save energy, I installed a heat pump water heater. I live in the US SE (technically a subtropical rainforest) so the heating of the water is essentially "free cooling / dehumidifying" for all the non-HVAC-heat days of the year (~9 months). During the brief winter, it switches over to standard dual 4500W heating elements.
There is a HVAC cost because the ERV is only ~60-75% efficient (at recovering heat/humidity with external supply air exchange), depending on the cfm/setting... but it gets rid of every stink, and you smell the morning dew and approaching thunderstorms. As is recommended, I leave mine on 24/7 — it has a boost mode which can be activated with switches wired anywhere else (e.g. bathroom, for during showers)... I plan to use a wallswitch timer for this temporary airflow increase, because the 24/7 setting I've set is 70% efficient, and at MAX it drops to only 60% energy recover.
The Panasonic unit I installed was ~$600, plus an additional $100 in venting. Took me about eight hours to DIY install (but I have decades of blue collar electric under my belt and am familiar with house). This would have probably been bid out ~$2500 if a company were doing it, on a simple install (i.e. <25ft ducting to non-roof penetration).
I think either DIY or Pro expense would be worth it, particularly if your air is stale / litter box / subtropical humidity. Modern building codes require HRVs/ERVs in most new construction, so if your building is even just a couple decades older, ERVs are worth looking in to (HRV if you live in desert climates).
[0] https://en.wikipedia.org/wiki/Heat_recovery_ventilation#Fixe...
[example] https://www.homedepot.com/p/Panasonic-WhisperComfort-60-20-5...
[see also] https://en.wikipedia.org/wiki/Indoor_air_quality#Improvement...