Types Of Ventilators
A heat recovery ventilator uses the air being exhausted from the home to preheat or cool the incoming air. These units are recommended for hot/dry climates. The system is usually activated by a timer control. In the typical system, the control starts and stops an intake and exhaust fan on a scheduled basis. The two different air streams pass through opposite sides of a heat exchanger where heat is transferred from the warmer air to the colder air. This fresh air is then distributed through a duct system to the home. Typically, the system uses the existing hvac system ducts. An energy recovery ventilator is usually used in warm /humid areas where it is desired to lower the humidity of the incoming air as well as cold/dry areas where it is a priority to retain the moisture in the home. These units work in much the same way except the heat exchanger is replaced with a special membrane called a core. This core allows moisture to pass from one air stream to the other as well as the heat. This is necessary in warm/humid climates to minimize the increase in humidity during operation. The excess humidity would otherwise have to be removed by the homes' air conditioner. In cold/dry areas, the ERV is used to preserve the indoor moisture so that the operation of a humidifying system is minimized. Total recovery ventilators combine both types into one unit. They are normally used in areas with cold winters and hot/humid summers. The right type of unit for your home will depend on your location. They can be an independently ducted system, integrated into an existing ducted hvac system, or window/wall mounted units.