Making sure that you change out your furnace filter is a crucial aspect of home furnace maintenance, and part of the process that many people neglect—sometimes because they’re not entirely sure why it’s important, and sometimes because they’re just not sure how to go about the process. 

Well, this is very understandable. 

A furnace is a somewhat complicated piece of equipment. And honestly—when it comes to something that’s designed to create enough heat to warm your entire home, you may be a little bit nervous about performing this type of maintenance yourself—out of fear that you may mess something up or throw something out of whack. 

But contrary to popular belief, replacing your furnace filter(s) doesn’t have to be a complicated chore. 

And in this blog post, you’re going to learn the vital basics that you need to know to perform this step as the months turn cold and you get ready to fire up your furnace for the winter. 

Is It Important To Change Your Furnace Filters?

Yes. It’s crucial to perform this basic maintenance step on a regular and recurring basis, for several reasons. 

Not only will this help to keep your circulating air cleaner, but it’ll also help to lengthen the lifespan of your furnace—and will likely prevent inconvenient and costly breakdowns in the future.

Replacing your filter(s) doesn’t take long, and it’s not expensive. And in the long run, it’s absolutely worth it in the money it will save you as an investment in the longevity of your heating system.  

Choosing The Right Furnace Filter

You’ll want to look at a few different factors before ordering or purchasing a new filter—just to ensure that you’re getting the right one for the job. 


The size of the filter is actually really important. One thing that you don’t want to do is just ‘guestimate’ and try to fit a slightly off-sized filter into the wrong slot. 

Your furnace/system was designed to use a filter of a very specific and particular size—so make sure that you consult your furnace literature or check for measurements on the side of the unit to find the actual filter size. 


The ‘thickness’ of the filter will also matter. Your furnace will require a filter of a certain thickness—and using a filter of the appropriate dimensions will provide you with a tighter seal that’ll help to keep air from escaping or moving around the filter. 

MERV Rating

The MERV rating (Minimum Efficiency Reporting Value rating) is basically a measurement of how well the filter works to keep debris from moving through your system. 

The higher the MERV rating, the better the filter will work. 

For most households, you’ll want to make sure that you’re using filters with a MERV rating of 10. 

But if someone in the home suffers from allergies, and/or if air purity is an especially significant concern, then you’ll want to buy a filter with a MERV rating of 12 or higher. 

Replacing Your Furnace Filter – The Basics

Where Do You Find Your Filter?

Your filter will be located along the return air duct. Somewhere in your home, there’ll likely be one or more return air duct openings that are covered with a grill—and they should have filters installed in them. 

Those are the filters you’ll want to replace. 

Your furnace may also require a filter installed closer to the unit—at the very end of the return air duct. So make sure to check there as well. 

How Often Should You Replace Your Filters?

In most cases, you’ll want to replace all of your furnace filters every three months

With that being said—there are a lot of factors that can play into this. 

If you buy higher-quality filters, and/or if you don’t run your unit all the time, then you may not need to replace the filters as often. 

If you have pets, you may actually need to replace them more often, just to make sure that you don’t end up with pet-hair-clogged filters before the three-month time is up.

Changing The Filters

Changing the filters is actually the easiest part of the process! 

Every system is a little bit different—but all you’ll need to do is open the filter slot, slide out the old filter, and replace it with the new one.  


Now you know everything you need to know about changing your home furnace filters. 

Keep in mind that if you need some help with this step, you can always give us a call. We could do it for you, or we could come out and walk you through it the first time to help you locate the filters and understand exactly how to get them changed correctly. 

So don’t hesitate to reach out if you need some assistance.