How often do I need to change my furnaces filter? | Home Comfort Inc.

How often do I need to change my furnaces filter?

The short answer is as often as they get dirty. However the size of your filter and your home environment play a big role in how often you change your filter.

The performance of a filter is related to it’s thickness, regardless of outside dimensions.  There are 1 inch thick, 2 inch thick, 4 inch thick and 5 inch thick filters.  Your furnace is designed to accept only one size (possibly 1 or 2 may work in one furnace).

The next consideration is environmental.  If you live on a gravel road and have 10 indoor cats shedding constantly, you will need to change your filter more frequently than someone with no pets, no kids, no husband and who never opens their windows.

So the best way to determine your personal frequency is evaluate your environment and then begin checking your filter.  Shut off the furnace at the thermostat and remove your filter. If the filter is obviously dirty change it, if not obvious, hold it up to the window and if you can see daylight through it it is still good, if you cannot see daylight then it is time to change it.

Rules of thumbs are 1 inch filters change at least every three months if not sooner, 2 inch filters 4 months, 4 inch filters can last 6 to 8 months and 5 inch filters can last as long as a year depending on the quality.

If you can see dirt on your filter it is about 50% plugged.