HRV’s are essentially noses on houses: they consist of two ventilation ducts running next to one another passing between the inside and the outside of a house. One carries cool, fresh air in; the other carries moist, stale air out. The clever bit is that the airstreams run through a device called a heat exchanger which allows the outgoing air to pass most of its heat to the incoming air without the two airstreams actually mixing together.
HRVs and ERVs have an obvious appeal: they give you a warm well ventilated home and stop you from “emptying your wallet” into the atmosphere every time you open your windows. In winter, they can help save on your heating bills; in summer, they reduce the need for air conditioning. Typically, they retain about two thirds to three quarters of the heat that would normally be lost from your home through ventilation.
Improves Indoor Environment
By keeping excess moisture out of your home, they’re better for your furnishings and health by keeping the “climate” inside your home at a more constant level.
Reduces Environmental Impact
Reduces energy consumption-related green house gas emissions due to heat recovery that offsets energy otherwise used to heat ventilation air.