How often you change your furnace filter depends on a series of factors that are relevant to the interior of your home. Regardless of the unique circumstances of your home, however, all furnace filters do require to be replaced at regular intervals in order to offer you the kind of protection that you’ve come to expect from them. These filters can become choked with dust, meaning that they will not act as an effective filter after some time, and cause your furnace to run harder if the filter isn’t cleaned or replaced.
Furnace Filters
Furnace Filters
Now that you know what can happen if you don’t change your furnace filter, let’s talk about when it’s best to change it. If you keep this information in mind, you’ll be able to change out your filter long before the built-up dust becomes an issue.

Do you have pets?

Pet hair and dander gets into absolutely everything. If you’re a pet owner, we’re sure that you already know this. Multiple animals, especially long-haired four-legged friends, typically place a greater strain on one’s furnace filter and require that it be changed more often than if there were zero pets inside of the household.
Most manufacturers recommend changing your furnace filter every three months or so, but the presence of pets can reduce this to every two months due to the addition of fur and dander. Tip: Check the furnace filter size, whether it is 16x20x1 filter or 18x20x1 filter etc and buy the right size.

Is dust a consistent issue?

Do you live on a farm? Do you have a lot of activity that goes from the outdoors to the inside of your home? If so, your living space might be experiencing more dust than the average house otherwise would. Dust is the biggest culprit in the clogging up of furnace filters, and if you live in a place where dust is a consistent issue that you have to clean up time and time again, you can bet that your furnace filter needs a little extra TLC too.

If dust is a problem in your home that you always seem to be fighting against, you’ll likely need to change your filter every couple of months instead of every three. This is also true if you tend to keep your windows open most of the time, because doing so invites the elements of outside, inside.

Does anybody smoke in your home?

The addition of cigarette smoke in the home places an added strain on your furnace filter, which requires that it be changed more often than if nobody smoked inside. If there is more than one smoker inside of the home on a regular basis, then you might find yourself needing to change your filter on a monthly basis.

Do you use the AC and heat often?

The blowing of the fans that are a part of your AC or heating unit can cause dust and other airborne nuisances to swirl around your home and inevitably get trapped within your furnace filter. The longer you keep these units running for, the more likely it is that you will be doing a monthly change of your filter. If these items are running on a daily basis year-round, you can probably expect to be changing your filter every  month.