How Frequently Should You Change the Furnace Filter?

How Frequently Should You Change the Furnace Filter?

Checking your air filter regularly will prolong the system’s lifespan and help keep your monthly energy bill in check. Experts suggest inspecting your furnace’s filter every month, particularly during furnace service by professionals in Redding, CA.

When Should The Furnace's Filter Be Replaced?

The rule of thumb for furnace replacement by experts is to replace the furnace filter every 90 days or every three months. However, this is contingent on the thickness of the filter. Experts recommend changing filters under 2 inches in thickness at 30 and 90 days intervals. Filters of three or four inches can last between 6 and 9 months, and filters up to 6 inches in thickness can be replaced annually.

According to experts for furnace repair Redding CA, the air quality in the area could influence the frequency with which your furnace’s filter needs replacement. Examining the filter is the most effective way to determine when to replace it. If it’s gray and covered in dirt and dust, it’s time to replace it.

Dander and pet fur will block the filter fast, so you’ll need to replace it more often. If you have only one pet, furnace replacement experts recommend changing one to three inches of filters every two months.

Signs to change the filter right away

  • Dirty filter: If the filter appears visible to be dirty or dusty, make sure to replace it.
  • Dust everywhere: If you see the dust more often, you may have to replace your furnace’s filter more frequently.
  • Regular usage of HVAC: If your HVAC is turning on more often and for more extended periods, it could indicate that you should replace it.
  • Smell: If your furnace emits a burning smell, an old filter might be the cause.

Factors That Determine When To Change The Filter

Filter Thickness

The thickness of the filter you are using also influences the frequency at which you need to replace it. You must change even the most robust filters every 6-12 months.


If you suffer from an allergy to pet dander or dust, changing the air filter more frequently than once every 90 days is recommended. Replace your filters every 60 days. If you are still experiencing these signs, think about changing your filters each month or switching to pleated filters.


If you have pets, you might need to clean your furnace’s filters at least every two months. The replacement frequency can increase when the weather gets hot and your pets begin to shed.

Home Size

According to experts for furnace service Redding CA, if you reside in a large house, you have more air moving through your house and the furnace’s filter.

Smoking Indoors

Smoke can wear down the filter quickly, particularly when many people in the house smoke. If one person smokes indoors, replacing the filter at least every 60 days is recommended. If several people in your household smoke, you’ll need to switch to a more robust filter and replace it more often, approximately once per month for filters less than 2 inches or every three months for filters between 5 and 6 inches.

Open Doors And Windows

Your furnace’s filter must work harder to clean out dirt and dust present inside your home.

If you open your windows and doors frequently during warmer months, replacing the filters on your thinner ones at least every month and the more robust filters at least once every three months is recommended.

Air-O Service HVAC technician experts are ready to assist you if you’re looking for filters for your heating or air conditioner. We can provide you the best options depending on the condition of your house, the presence of allergies, or pets. Call us at 530-221-4691 to schedule an appointment for heating and air Redding CA.

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