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Is It Time To Change Your Furnace Filter?

A furnace filter may be a small component, but it requires regular cleaning and changing. Without these, the filter will soon become clogged and cause a lot of other problems on the furnace. The longer it remains dirty or clogged, the more you increase the chances of spending more money on costly furnace repairs. A clean filter also improves the air quality in the house and protects the rest of the furnace components from dirt and dust. How often to replace furnace filters depends on each person’s preference, but the recommended period is every three months. Inspection should be done every month, and if you find a greyish colour or dirt buildup, you can change it before the 90 days are over.

Factors Determining How Often to Change the Furnace Filter

Filter type: 1 and 3-inch filters are the two most common sizes available. The smaller size will need replacement more frequently than the larger one, which can go up to three months. However, you still need to follow the recommendations of the manufacturer.

The health of household members: If one or more family members have respiratory health issues, a dirty filter will aggravate their condition. The only way to avoid breathing issues and allergies is by keeping the indoor air clean by always having a clean filter.

Home conditions and lifestyle choices: If you choose to have pets, the chances are that pet fur, and other debris will accumulate on the filter quickly. A lot of dust, especially during a renovation, can also cause clogging, which will require more frequent changing of the filter. Similarly, filters used in areas with high humidity will not last long like those used in dry areas because the excess moisture will prevent the optimal flow of air.

How the HVAC is used: Over-reliance on the heating and cooling systems also determines furnace filter replacement frequency. The more the furnace or air conditioner is used, the more the filter will get dirty, requiring replacement or furnace repair.

Having a smoking family member: Smoking inside the house increases the number of particles, which may overwhelm the filter and decrease its lifespan. You should check it regularly and replace it whenever there is a visible colour change.

Open windows and doors: Most people leave doors and windows open during summer, which is understandable considering the level of heat in Toronto. While this may provide a cooling effect and increase comfort, it leads to the accumulation of more dirt that takes a toll on the filter.

How to Change the Furnace Filter

  1. Turn off the furnace.
  2. Remove the air filter panel, which is located at the bottom of the furnace. It will expose an open compartment that has a filter with metal brackets on each side.
  3. The enclosure limits the space for the filter, which means you have to be careful when trying to remove it. Move it sideways gently until you can pull out one end, then slowly take it out of the compartment.
  4. Check whether it is a disposable or permanent filter. The latter is usually framed with plastic, while the former is not. If it is disposable, discard it and install a new one. If not, clean it with a vacuum cleaner and put it back in place. A soft brush or clean cloth can also clean the surface of the filter properly.
  5. Put it back in place, taking care not to damage any other component in the panel.

Other Tips

  • Always choose the right size of filter to replace the old one. Check the filter frame for the size measurements.
  • It is not advisable to use water on the filter, but you can use a moist, lint-free cloth. Give it ample time to dry afterwards before putting it back.
  • Check the perimeter of the filter for an arrow that shows the direction of the airflow, then insert the new filter in the same way. In most cases, the arrow points to the top of the furnace.


How often should I change my furnace filter remains one of the most popular questions among homeowners, and the answer differs with every person. The needs of the family and other factors mentioned above determine how often every person changes their filter. If you need further help in filter cleaning or replacement, don’t hesitate to call Air Makers.

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