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Furnace Filter Basics

Furnace Filter Basics
The furnace filter is an essential component of your home’s heating system. Its primary function is to prevent particles and debris from the air entering your furnace in order to safeguard your furnace’s mechanical components, such as the motor.

Here are some general guidelines to ensure that your filter is effective:

Consider leaving your furnace fan running all the time. Continuously running your fan to provide continuous airflow and filtration. Keep in mind that if you haven’t done it before, you’ll need to check your furnace filter more frequently because running the fan will pull more air through the filter, causing it to fill up faster.

Check and replace your filter regularly – This should be done every three months, but more frequently if conditions warrant (for example, if you live in a dusty location, have pets who shed, or use your furnace fan continually).

More “Merv” isn’t necessarily a good thing – A good Merv rating for home use is between 5 and 8 to balance particle trapping with air movement. Before utilizing a very high Merv filter, check with an HVAC specialist because your system may be unable to withstand the airdrop (reduction in airflow) induced by a very high-efficiency filter. If you have a 2″ or 4″ filter slot, using a filter with a higher Merv rating will be less of an issue because the larger surface area of a thicker filter creates less air resistance.

Never attempt to clean a disposable filter – this is because the materials degrade with time and are not intended to be reused or cleaned.

If your filter does not fit, it will not filter! Because air chooses the path of least resistance, it is critical that your filter fits in as tightly as possible. It must extend to the end of the filter track, with no obvious gaps on either the plenum or the furnace side. If your furnace requires a specialty size, you may either purchase one or have your filter slot altered to accommodate a standard size. If there is a space between the sides of the filter and the door, a piece of duct tape down the slot to close the gaps is an excellent suggestion.
Duct Filter Basics-min
Air filtration system removing airborne particles and improving indoor air quality