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When Should I Change My Furnace Filter?


If you’ve spent much time on our blog, or any HVAC contractor’s really, you will have read time and time again about how important changing your furnace’s air filter is. But just telling you it needs to be done is only half of the story! Knowing how often it needs to be done is just as important, if not more.

Not sure how often you should be changing your air filter? The specialists at North Town Home Services can give you the rundown on the why, the how often, and the small details that might change the answers around. Get ready to have all your questions answered!

Need an expert to handle your filter changes, or looking for professional furnace tune-up and maintenance experts in Chicago? Contact our HVAC specialists today!

Why a Furnace Filter Change is Important

Put very simply, the furnace filter is responsible for keeping air flow healthy in the closed loop of your heating system. Our homes are extremely dense with the same air pollutants that can be found outside, containing all of the dust, dander, pollen, and more—but in considerably thicker concentrations.

If these are left to run amok in your furnace system and the filter is never changed, it will quickly result restricted airflow of the unit. This can translate to lower efficiency ratings, uneven heating, and can even cause a furnace breakdown that will require professional repair!

How Often a Furnace Filter Needs to be Changed

The answer here is going to differ a little bit based on a few important factors:

  • The type of air filter you have. A standard 3” fiberglass filter can only handle so much abuse, meaning it needs to be changed frequently. On the other hand, a pleated polyester or a thicker filter might only need changing once every three months because they can stand up to wear and time better.
  • The size of your home. How large your home is will play a role through sheer dust accumulation and the amount of mess that can fit invisibly in a given space. Usually a larger home means a more frequent change.
  • The occupants in your home. Every person and pet (especially every pet) will mean more dander and more dust, which will mean more filter wear.
  • Whether or not you smoke. Smoking introduces quite a lot of pollution into the air in our homes, and thus the filter will be catching a lot more ash and dust particles.
  • Where exactly you live. Living near commercial areas can mean vehicle and combustion pollution getting into home air, while a countryside or suburb home might encounter more pollen.
  • And more!

A whole lot can play a role in how long your filter is going to last. If you’re looking for a good rule of thumb or ballpark estimate, every two to three months is the usual standard for swapping out a furnace filter. But the best answer is when it needs to be changed.

We strongly recommend adding inspecting your furnace and air conditioner filters regularly. Nothing crazy—once a month is fine. By quickly popping off the furnace’s front cover you can check the filter and start to get a feel for how long your filters last. From there you can change it on time every time, ensuring your furnace is operating at optimal efficiency and health all season long.

An important part of keeping your filter and furnace clean is annual furnace maintenance. Be sure to schedule yours with our top-class furnace technicians in Chicago today if you missed it this year!

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