Most homeowners don’t change their furnace’s air filter as often as they should. This can lead to a host of problems. How often you need to change it depends on several factors.

What’s Does a Filter Do?

The furnace filter’s job is to trap airborne particles. Its main purpose is to keep your heating and cooling system clean, but it also improves the indoor air quality of your home.

Why Does the Furnace Filter Need to Be Changed?

When the furnace filter gets dirty, it restricts airflow. This makes your furnace and air conditioner work harder, which shortens their lifespan and increases your energy bills.

How Often Should I Change the Furnace Filter?

You should replace the furnace filter at least every 90 days. You may need to change it more often depending on the situation in your household. The filter is either located in the return duct or in a slot on the furnace.

Number of Occupants

You’ll need to change the furnace filter more often in a home with a large family than one with just one or two people. The more people in your home, the more contaminants are brought into it.


If you have a cat or dog, you’ll need to change the furnace filter more frequently. These pets shed fur and produce dander, both of which are collected by the filter. If you have a couple of pets, you may need to change the furnace filter every 30 days.


You may need to change the filter more often than every 90 days if someone in your household suffers from allergies. Changing the furnace filter more often can reduce the contaminants that cause allergy symptoms to occur.

Gatewood Heating & Air Conditioning, Inc. in Sonora, CA changes filters as needed when we perform a furnace or an air conditioner tune-up. You can also rely on us for the repair and installation of heating and cooling equipment. Other services we offer include air quality improvement, ventilation, humidifiers, and smart thermostats. Get in touch with us today to schedule an appointment.

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