Choosing a Furnace Filter

The first thing to remember is that a furnace filters primary purpose is to protect the furnace equipment by trapping large particles and dust from getting into the furnace. Beyond that your selection of a furnace filter should be determine by the level of cleaning you want from the filter.

NOTE: Since furnace filters only work when the furnace fan is running, you should to run the furnace fan all the time to get the most benefits out of your furnace filter.

If allergies and respiratory problems aren’t a concern for your family, a disposable fiberglass or cellulose filter will do the job just fine. These filters are the least expensive and are will only remove the larger particles and dust. Remember to change these types of filters at least once a month during periods when the furnace is in use.

The next step up would be a washable or electrostatic filter. These filters are only fractionally more effective than the disposable, but the can be washed and reused. Again these should be removed and washed at least monthly and will typically last around 3 to 5 years.

If you are concerned about allergens, then a pleated filter is a very cost effective option. These filters have a lot greater surface area to remove particles and are very effective at removing even small particles. This is the best option for families that need protection, but can't afford to have an air filtration system installed.

Electronic air cleaners or HEPA Bypass Filters are the best at removing harmful particles from the air. These are considerably more expensive ($650+) and need to be professionally installed within your return ductwork path. This is the best option if you or someone in your family has a history of respiratory problems, the high initial cost can be offset with lower medical bills.