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How Often Should You Change Your Furnace Filter?

Published by Luke Weiden

It’s important to change your furnace filter regularly. However, “regularly” can mean monthly, every 3 months, every 12 months, or any time in between. The thickness of your filter and the condition of your home’s air play a large part in how often you should change your furnace filter.

As a rule of thumb, 1” filters should be changed every 90 days and 5” filters will last you six months. But these general guidelines may not accurately reflect your specific needs. Until you know how long it takes to dirty a filter in your home, check it once a month.

How To Tell If Your Furnace Filter Needs Changing

If your filter restricts airflow, it forces your hvac system to work harder and should be changed. Shining a light on a dirty air filter is one of the easiest ways to test whether or not it’s actually limiting air flow. If light can’t pass through the hvac air filter, air won’t stand a chance.

Another way to test the air flow of your heating or air conditioning system is to tape a ribbon or string to one of your registers (vents). Pay attention to how much the ribbon moves with your filter installed. Then remove the air filter from your furnace and watch the ribbon again. If you notice much of a difference between the two tests, it’s time to change out the filter.

Can Your Run A Furnace Without A Filter?

No, furnaces and heat pumps need a filter to protect the blower fan from debris in your air. It’s ok to briefly run the furnace without a filter when changing it or to check the airflow of your heating system. But doing so any longer than necessary could damage the system and force you to pay for expensive repairs.

Air filters help your heating and cooling systems run more efficiently while improving indoor air quality. Furnaces pull cool air in through return ducts, heat it, and push the now warm air through vents around your home. As air passes through the return ducts, it often brings dust and other contaminants with it. The furnace filter prevents these contaminants from entering the furnace and interfering with its components.

A dirty filter reduces your furnace’s energy efficiency, leading to higher energy costs. So if you notice your energy bills climbing and can’t figure out why, you might want to check your furnace filter.

At Deljo heating and cooling, we offer furnace maintenance in Chicago and throughout the greater Chicagoland area. Our gold star HVAC maintenance plan is a great way to save money on maintenance for both your heating and cooling systems. Give us a call today to set up an appointment!

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