Changing and cleaning the furnace filter are some of the simplest things you can do to extend the proper functioning of your home heating system. While furnace filters were primarily used for the protection of the furnace itself, there has been an increasing trend in the belief that a high grade filter will also increase the over all air quality of the house.
There are several types and styles of furnace filters our there and here are the most common:
Fiberglass furnace filters are the cheapest to buy but block the largest dirt and dust particles and thus protect the furnace as intended. Because the fiberglass filter is not meshed very tightly, the smaller particles like pollen and mold can get through.
Studies by the CMHC have shown however that even the most expensive furnace filters that were designed to catch even the smallest particles and spores do not greatly increase air quality. The reason is because the main cause of poor air quality in households has nothing to do with the furnace itself. Particle density in the air has to do with how much the dust is being stirred up by activity in the house itself. This would include smoking, doing laundry, pets and dust around the house.
The best filter in tests is the ESP furnace filters. ESP filters work by producing an ionized electrical field that “magnetizes” pollutant particles and collects them on the filter material. And of course it does collect the most particles, but may not increase you homes air quality because the filter is located in the basement away from the air you actually want filtered.
There are also washable electrostatic furnace filters that collect dust and debris through a static charge and pleated mesh type filters. The pleats create more surface area to trap more particles and so are slightly more effective than the electrostatic type filter.
High Efficiency Particulate Air filters or HEPA for short, are what hospitals and other areas where air quality is of utmost importance use. While they may be the highest quality, they also block air flow and so are not efficient when used in a household setting.
So now that you understand where the dirt and dust actually comes from, choosing what type of furnace filter you need isn’t really such a big deal. The real purpose of the filter is to protect the furnace and not your lungs. The lung protection is better dealt with on a household cleaning level. While the furnace filter will contribute to your air quality some what, the only real concern that you should have is that you change it every month or so.