The answer is: quite a lot! Energy recovery ventilators (ERVs) are special devices that professionals can install into HVAC systems to allow for better indoor air quality without the sacrifice of significant energy efficiency indoors.
Here is the conundrum that an ERV helps a homeowner face: The best way to enjoy fresher air in your house is to allow for more air circulation from outside. An influx of outdoor air replaces the stale indoor air and sweeps out numerous pollutants. But to bring in that outdoor air requires opening up windows and doors, and this isn’t ideal during the height of winter or summer. Opening up the house either brings in the heat (summer) or lets the heat escape (winter). An HVAC system must work overtime trying to maintain comfortable levels inside when the house is open like that, and this wastes energy.
How does an ERV help overcome this problem? We’ll get into that below.