Here Are Circumstances Affecting Air Filter Replacement Frequency

The standard instruction for homeowners on the frequency with which they should inspect the air filter in their forced-air heating and cooling system is to do it monthly. But that’s a very general recommendation and may differ based on a variety of factors, including climate, amount of usage, health concerns and more. The main goal, no matter what factors are at play, is to make sure to replace the air filter before it gets clogged with dust and debris (or clean it in the case of washable filters).

Why Is a Clean Filter So Important?

You shouldn’t allow the filter that works with your forced-air furnace, air conditioner or heat pump to become clogged with dust and debris for a variety of reasons. They include:

• A dirty filter will impede the flow of air in your HVAC system. This will force the blower motor to work harder and longer to circulate conditioned air in the house and draw it back to be heated or cooled again. This wastes energy, increases costs, leads to unbalanced air circulation, and stresses the equipment, leading to breakdowns and a shorter service life.

• When the filter is clogged, some of those dirt and dust particles will end up falling on sensitive components of your HVAC system, creating friction and stress. This will result in some of the negative effects cited in the previous bullet point.

• A clogged filter can’t do its important job of removing airborne contaminants and enhancing indoor air quality as well as a fresh filter can.

How Often Should You Change the Filter?

As stated, this depends on a number of factors, though getting in the habit of inspecting the filter every month is a smart practice no matter what other factors are involved. It just take a minute to do this simple task.

Factors influencing the frequency of replacing or cleaning the filter include:

• Climate. If you live in an area where the temperatures don’t get extremely warm or cold (San Diego, for instance), your HVAC system will not be running constantly, so filter changes won’t be required as often as if you lived in a hot-summer climate (Los Angeles, Florida, Texas, southern Arizona, etc.) or a cold-winter climate (Midwest, Northeast, Rocky Mountain West, etc.). The vast majority of Americans (and Canadians) do live in areas where their HVAC systems are in heavy use during certain parts of the year.

• Seasonal. In general, your HVAC system’s air filter won’t need to be replaced as much when the system’s not running as much. This rule applies both to climate conditions related to geography (previous bullet point) and seasonal conditions. So here in Cincinnati, you shouldn’t need to replace the filter as often as monthly in the bridge months between fall and winter, and spring and summer. You probably should replace the filter at least monthly during the heavy-use summer months for the AC (or heat pump) and heavy-use winter months for the furnace (or heat pump).

Indoor Air Quality – Two Concerns

• Indoor air quality – special circumstances. If there’s some factor that’s making your indoor air dirtier than in an ordinary situation, you’ll want to inspect and if necessary replace the air filter more often. Examples of these circumstances are living on a dirt road or near an industrial facility that emits pollutants, or having a home improvement project that’s resulting in dirtier than usual indoor air.

• Indoor air quality – health of home occupants. If you have family members or other members of your household who are suffering from allergies or other respiratory issues, clean indoor air is critical. You can’t afford to risk the health of family members by allowing the furnace or AC filter to become clogged with dust and debris. Make sure the filter is replaced regularly, and don’t skimp on the type of filter either. Avoid buying cheap filters that only remove the largest airborne particulates. However, you should also avoid using filters that are ultra-efficient, since their dense filtration media will impede airflow.