How Often Should You Replace Your Furnace Filter

How Often Should You Replace Your Furnace Filter?

Can you imagine your life without a furnace in the middle of a cold winter? Especially if you live in the colder regions of the country, a furnace is one of the most important HVAC units for you. But all HVAC units come with an air filter, and a furnace is no different. You need to replace the filter every few months to keep the indoor airflow clean and healthy. A dirty filter can pollute the indoor air in a way that can become dangerous for a respiratory disease patient.

Why Should You Replace Your Furnace Filter?

If you think about it, the air filter has the dirtiest job among all the different parts of a furnace. The main job of an air filter is to trap harmful, unwanted particles such as dust, pet dander, microbes, and other allergens. The HVAC air filters trap these elements and circulate clean air throughout the house. So replacing the dirty filter with a clean, well-performing air filter inside the furnace is very important.

How Often Should You Change the Filter?

When it comes to changing the filter inside your HVAC unit, it is important to know when and how to change the filter to get the best output with the least expense. Depending on the house’s air quality and the person’s requirement, the need for replacement can vary.

Depending on Air Quality

Sometimes the air in a certain area contains more duct particles than usual. In that case, even a well-performing filter cannot last for a long time. In situations like this, it is very important to check the filter condition every month, as in every 30 days. You can use filters of various sizes as well, if the unit permits, such as a 13X21.5X1 air filters or a 15.25×15.25×1 air filters.

Depending on Requirements

If the living area needs to be highly sterilized, the filter requirements are even more specified. Like in hospitals, the filter needs to be very dense with a high MERV rating. If you have any respiratory disease like asthma, the air quality needs to be extra crisp. For these needs, the air filter needs to be changed more frequently.

Depending on Owning Pets

Having pets can change the complete notion of indoor air. Pets, like furry animals, shed much of their fur throughout the day. For these pets, the air gets polluted with pet dander and fluff. The filter has to trap all these things, making it clogged in no time. Some animals shed more than others. Depending on whether you own pets or not and what type of pet you have, the regularity in which you need to replace the air filter can vary.

Depending on Filter Thickness

Each air filters supplier tries to supply a variety of sizes and thickness of air filters. It is recommended that any filter with a thickness of 2 inches or less needs to be changed every 90 days. And the thicker filters of 4 to 5 inches in thickness can last for around six months. But it is always wise to keep checking the filters at regular intervals.


If you need a short answer to the question of replacing your air filter for your furnace, the solution is that you have to change the filter after 90 days. But this straight-cut solution will not work for all households. According to the experts from Simply Filters, how often you need to replace the filter varies upon the difference in requirements, location, and lifestyle. Regular assessment is absolutely necessary. If the filter quality seems compromised after the checkup, replacing it would be the best decision.