Air exchanges, often referred to as heat-recovery ventilators, draw in fresh outside air and replace the stale inside air within your home. To do this, cool outside air is drawn in through a heat exchanger where it is warmed before being released throughout your home through the ductwork. This saves you money on heating costs. The stale air is already warm, so it does the heating through the heat exchanger before it is released outside the home.
You may ask how we are to know the outside air is clean? Well, that has been taken care of with a filtering system that filters the incoming air. The filter cleans the outside fresh air while it enters in the home and this keeps the components of the heat exchanger and duct system free of debris.
Filters should be changed monthly during the heating season or as needed. Remember, plugged filters diminish the efficiency of the unit.
The less obvious reason for clean, fresh air is for a healty home. This also includes the health of family members in the home. Lack of air flow and the presence of stale, moist air can cause moldy, musty air. Rooms subject to high humidity, especially bathrooms, can become mildew filled. In this case, exhaust fans remove the moisture.