How Often Should I Change My Air Filter? Here’s What to Know

updated Oct 21, 2020
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If you’ve ever had your furnace fail in the dead of winter—or your air conditioner kick out on you in the sweltering heat of summer—you know that indoor comfort does not come cheap. The cost to repair or replace an old unit is steep, a new window AC can be difficult to replace, and portable air conditioners aren’t too wallet-friendly either. Your safest bet is to take the steps now to make sure yours has a long and happy life. First step? Make sure you change the air filter as often as necessary.

But how often is necessary when it comes to replacing your air filter? Well, it depends on a few different things, starting with the type of filter you have.

Furnace Air Filter

These types of air filters are part of a built-in system in your home. Replacing the filter is much, much simpler (and way cheaper) than the whole system, so it’s good to follow these rules of thumb.

How can I tell if the air filter needs changing?

The easiest way to tell is just by looking at the filter itself. If it looks dusty and dirty, and no longer resembles its original state, it’s time to replace. ReddiHVAC, a company based out of Kansas, recommends that if your home is especially dusty and your system has been running more frequently, it’s most likely time to change it out. 

Can I clean the air filter instead of replacing?

Yes, if your filter is reusable you can give it a good washing. But in most cases you’ll have to replace your filter eventually. The manufacturer guide or sticker on your furnace should be able to tell you how often they recommend changing your filter out for your specific model.

How can I make my air filter last longer?

If you regularly vacuum dust and loose dirt from your air filter, you can double the life of it. A normal person without a shedding pet or severe allergies should change their air filter roughly four times each year, but thorough cleaning can cut that down to just two times.

AC Air Filter

There aren’t too many differences in changing and cleaning furnace filters and those for smaller AC units and portable versions. AC air filters also need frequent cleaning and changing, and these tips should help keep it running in tip-top shape.

How can I tell if the air filter needs changing?

The first thing to check is if your filter looks dirty, or if it’s been a couple of months since you’ve last changed it, it’s time. Sun Kool Air Conditioning Inc. out of Florida, states that there are several other ways to tell, too, including if your unit is overheating, if the cold air isn’t actually that cool, or if your electric bill has increased. 

Can I clean the air filter instead of replacing?

Be sure to check the owner’s manual or your manufacturer’s guide for specific instructions, but most filters can be cleaned. General Electric suggests vacuuming, dusting, and occasional bath in warm water with dishwashing soap or baking soda.

How can I make my air filter last longer?

Similarly to a furnace air filters, you can dust and vacuum debris from your AC air filter to extend its life. This will allow you to go a bit longer between changings and keeps your air filtration system in better condition. But keep in mind, that swapping out filters is a must eventually!