Energy recovery ventilation is a process for conserving energy by pre-treating fresh air with air from the exhaust system to expend less energy on heating and cooling. This allows for regular air exchange to keep an environment feeling fresh, while cutting energy costs. Better control over both temperature and humidity may be possible with an energy recovery ventilation system. It is possible to install new systems or retrofit existing ones to make them more environmentally friendly.
In cold weather, air from indoor areas will be warm from the heating system, and typically contains some moisture. It passes through a heat exchanger and pre-treats air from the outside to warm it up and transfer moisture, maintaining a comfortable humidity level. This air still needs heating, but is warmer than air fresh from the outside. The air vented from the heating system will be cool, as it loses heat through the heat exchanger.
When indoor air needs cooling because of heat, the same heat exchanger system transfers heat from the outside air coming in to the cold air being vented out. It will also transfer humidity, preventing internal humidity from getting too high in the summer heat. Air leaving structures in the hot months will be warm because of the heat it absorbs from outside air in the heat exchanger.
Using energy recovery ventilation cuts heating and cooling costs directly by getting the air closer to the needed temperature before it even enters a facility. In addition, an energy recovery ventilation system usually needs to be smaller, requiring less energy to install and run. The maintenance of consistent humidity can be beneficial as well. In the winter, heating often makes structures feel very dry and can lead to cracked skin and lips, eczema, and other forms of skin irritation. The transfer of humidity keeps the environment comfortable. In the summer, when indoor air might get too humid, heat and humidity exchange controls humidity levels to keep them at a reasonable range.
Heating and cooling companies can install and maintain energy recovery ventilation systems, including retrofits of older systems as well as brand new ones. The level of efficiency available varies, depending on the climate and the system. It is possible to use other measures for even better climate control, including insulated windows to prevent heat loss, strategic design to keep core areas of a structure at a stable temperature, and similar passive temperature control techniques.