Last updated on March 10th, 2024 at 03:32 pm

The filter takes out a lot of dander, hair, pollen, etc from the air as it is fed into the furnace.

If the filter is dirty, less air is fed into the heating system, which means…yep, you guessed it. The furnace has to work harder by staying on longer to heat the available air. And the longer it runs, the more it costs.

Some will advise you to change it every 60 or 90 days. I’d still recommend every 30 days, especially if you have pets or an older house with older ducts and furnace.

Of course if you have central air you’ll want to make sure that the filter is changed more often if the unit is using the same ducts.