How often should you change your air filter?

Easy breezy

A ombre purple and pink background with cut outs of different sized air filters surrounded by white sparkles.
(Image credit: Future / Amazon / Beth Mahoney)

You’ve treated yourself to a new air purifier or portable AC unit and you’re wondering if the maintenance is going to be a total pain (or... if you can just skip it). With it being such a spendy item, you obviously want to make sure that it lasts, and taking care of it is the best move you can make. That doesn't mean it comes naturally though. 

I’m right there with you. When I first got an air purifier, I had no idea how often the filters needed to be changed (or cleaned) or how important it was to actually change them. The result? A poorly working purifier that was doing very little to actually filter the air in my space and amp up the air quality. 

Confused by the ins and outs of keeping your air filters clean? Don’t panic. From your air purifiers to your air conditioning units, we’ve got you covered with all you need to know.

How often should you change your air filters?

The truth is, this depends on the device and filter. As a rule of thumb, replacing — or cleaning the filter if it's reusable — every three to six months is usually advisable. However, some manufacturers (usually ones that offer washable filters) say that you don't have to change your filters more than once a year. 

Obvi, the more you use it the more often the filter will need to be replaced. Oh and, FYI, if you have allergies or asthma, it's usually recommended that you swap out your filters a li'l more regularly. 

Why is changing your air filters regularly important?

In order to ensure that your air filters work effectively, it’s vital that they’re properly maintained. What happens if you let it slide? Nasty bacteria, dirt, and grime will start making a home in your device. 

This means that it probably won't run as well. If you have an air purifier, the air won't be nearly as clean. If you have an AC unit, it probably won't be cooling you down nearly as effectively or it'll have to work harder — costing you more money and energy. 

How can you tell if your air filters need changing?

A good starting point for knowing when your filters need changing is to read the manufacturer's instructions. Here, you'll find recommendations for changing the air filters. If you've lost the little paper book, check online! Alternatively, if you feel like your purifier or air conditioner isn’t working as effectively as it previously was, then there are some visual signs you can look out for. 

If you're noticing dirt or dust piling up on filters or can see black spots or patches, these are both signs that it's time for a filter change. If you’ve noticed that your purifier or AC has a damp or moldy smell, this could also indicate that there’s an issue with the filter and that it’s time to switch it out for a new one. 

What’s the difference between replacing and cleaning your air filters?

Different manufacturers offer a selection of filters with different care and cleaning requirements. While some filters are made to be used for a set period of time and then replaced, others can be washed and then reused. And, while some filters can be washed and reused again and again, others can only be reused once or twice. 

If the manufacturer recommends washing and reusing a filter, then the chances are that this should not impact the performance of the device, and should work just as well as fully replacing the filter. Here's to cleaner, cooler air!

Beth Mahoney
Freelance journalist

Hi! I’m Beth Mahoney and I’m a former staff writer at Real Homes. I’ve been a journalist for the national press for the past six years, specializing in commerce and trends-related lifestyle articles, from product reviews and listicles to guides and features. With an eye for pretty things (think: quirky wall prints, scalloped edge furniture, and decadent-looking tableware) but a limited budget, I love nothing more than a bargain buy.