How a residential HVAC system works...

1) The air is filtered and when using an advanced air cleaner with a high MERV rating (used to rate the effectiveness of air cleaners), the system has the ability to filter microscopic elements out of the air. These work much more effectively than normal furnace filters, and some models can even capture and kill the common flu virus! (for more information see: indoor air quality).

2) The air is cooled. The air is then pulled into the furnace by a variable speed furnace fan, and forced through the evaporator coil. An evaporator coil is a series of piping containing chilled refrigerant from the air conditioner (at a low pressure). The cold piping absorbs heat and causes moisture to condense, thus cooling and dehumidifying the air. This conditioned air is pushed on by the fan while the heated refrigerant is sent back outside to the air conditioner (condensing unit). The refrigerant is pressurized in the condensing unit which removes the heat. Then the cycle repeats.

3) Mold is killed & coil efficiency kept high. In the damp interior of an evaporator coil system, mold can grow which can affect not only the health of your family (mold spores in the air), but the health of your HVAC system by decreasing the efficiency of the evaporator coil. In the HVAC design example above, a UV lamp is mounted within the evaporator coil to prevent this. UV lamps are able to kill and prevent mold from growing, thus keeping your home healthy and your cooling efficiency high.

4) Cooled air sent back into the home. After leaving the evaporator coil, the cool, dehumidified air is pushed back into the home. In extremely humid climates, a separate dehumidifier can be installed to remove more humidity from the air than is removed by the evaporator coil.

5) Air is exchanged. At the top left of the above HVAC design sits a ventilator. Ventilators are quite amazing. They are part of complete indoor air quality solutions as they exchange fresh outdoor air for stale indoor air. They are able to do this with minimal loss of energy, and they retain the cooled and dehumidifed air your HVAC system worked hard to produce!

For more information visit http://www.stewartheatingandair.com/