Indoor Air Quality and Types of Filters
The quality of indoor air in your home is affected by sources of indoor air pollutants. These pollutants can originate inside your home or be drawn in from outdoors. Common sources include the construction of your home, people, animals, room furnishings such as carpeting, photocopiers, art supplies, etc. Particles of dust, fibers, mists, bioaerosols, and gases or vapors enter your home through these various sources. Home with forced air heating and/or cooling systems can utilize the fan on the furnace to circulate the air in the home 24 hours a day, 7 days a week. As the air passes through the return air duct system, it passes the furnace filter located before or at the point where the return air enters the furnace fan compartment.

There are basically five different types of filters for home use:

1. Disposable panel filters
The typical furnace filter provided with your furnace is the 'use once and throw away' filter. These primarily keep larger particles of dust and debris from clogging up the fan of your furnace. These types of filters are not really designed to help the indoor air quality of the home. Most furnace manufacturers recommend disposable filters be changed once every 90 days.

2. Electrostatic filters
At this time, we do not recommend electrostatic filters to be used on home furnaces. While they do help with the indoor air quality they load up very quickly, can potentially damage your furnace, and eventually lose their charge.

3. Media or Pleated Filters
The pleated media filter is built with an "accordian" style configuration, allowing for a larger surface area for the air to pass through than a flat panel filter. This increases the useful life of the filter and is the first practical one to help the indoor air quality of the home. The weave of the material in a pleated filter helps 'load' or gather the particles of duct on the material, which in turn helps slow down additional particles, etc. They are available in 1 inch, 2 inch and 4 inch widths. Pleated media filters can last anywhere from 90 days to one year, depending on the environment in which they are being used.

4. Electronic Filters
The most commonly known electronic filter in use today is the Honeywell Electronic Air Cleaner. Electronic air cleaners usually have a thin pre-filter to collect the larger particles of dust and debris, then pass through an electrically charged set of stainless steel plates that 'zap' the airborne dust and debris, as small as .001 mircons. The collector plates eventually build up a film of grime and dirt, that can be cleaned off in your dishwasher or by soaking the cells in a tub of soapy warm water. Once they air dry, they can be re-installed and ready to go back to work. Electronic cells also give off ozone. Some people are adversly affected by ozone, so some caution must be used. The cells typically need to be cleaned every 30 to 90 days.

5. Charcoal Filters
Charcoal filters do not help clean the air of dust, debris or particulates. Their only function is to help remove gases from the air stream. Cooking, smoking and other gaseous odors are absorbed into the activated charcoal. Once the charcoal is 'loaded' with gases, it must the replaced; it cannot be cleaned.
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