Heat Air Exchanger for Heat Recovery

An air-to-air exchanger is used to recover heating or cooling and to improve the air quality of the building that it serves. Typically an air exchanger has two fans, one blowing air into the house and one blowing air out of the house. In the winter time the one fan brings the outdoor cool air through the core warming it with the warm stale air you are exhausting. In the summer time the warm air from the outside will be cooled as it enters through the core to save on your cooling.

Air exchangers often are used to perform many functions such as reducing air contamination, heating or cooling air entering the building, and humidifying or dehumidifying air before it enters the building. Air to air heat exchangers or heat recovery ventilators, are used to provide a balanced flow of air into and out of a building. Ultimately an air exchangers main function is to switch the stale inside air with fresh outside air while exchanging the heat or cool in the process.

There is some controversy about the savings of exchangers. Not only does it require electricity to run the air exchanger, but the air the exchanger brings into your house must be brought up to temperature. This may require that more electric is used to cool your building or that more fuel is also required for heating.

The amount of air that these air exchangers bring into a home may vary depending on how the system has been installed. The codes in many places require a minimum amount of air to be exchanged. Check with your codes official to see what the requirements are for you.

Air exchangers can be a very good thing for many buildings. Especially those that are very large and typically have a lot of occupants with little natural air exchange from doors or windows being opened. However they are also a health hazard if they are not serviced

All air heat exchangers will require regular maintenance. The problem is that this is almost never performed by homeowners, and unless they know about the exchanger it is often overlooked by contractors during service calls. The real problem is that clogged, air-to-air exchangers can make the indoor air significantly worse than it would be without the system installed at all. If you have a home that already has a heat air exchanger, make sure that you keep it very well maintained or disconnect it.

Many air exchangers are controlled simply by on and off switches, but in some applications where the removal of humidity is required, then a humidistat can be used to turn the machine on and off to achieve the humidity level that you want. In cases where there may be a lot of humidity the air exchanger may not be enough to solve the problem. Other devices may be needed to lower the humidity to the level that you want.