How Often to Change Air Filters (2024)

Changing HVAC filters: a chore everyone sort of knows they ‘should do’, but that many people are unsure about. Why do I need to change them, and how often? Can I do it myself? Well, we’re experts on air vents around here, so if you’re wondering how often to change air filters, you’re in the right place.

Why Is It Important To Change Your Air Filter?

You’re trying to decide how often to change air filters. But why is it important in the first place?

Your air filter is a screen that the air in your home passes through as it is cycled through your ventilation system. It catches dirt, hair, and other pollutants. Over time, these build up on the filter and can eventually block the airflow.

While the filters are partially there to keep your air clean and protect your health and wellbeing, it is just as important that they protect the HVAC system itself. Without a filter, dirt will build up within the fan and the machinery itself, which will eventually cause damage to the system. 

If the filters aren’t changed regularly, they will get blocked and prevent air from moving through the ventilation system at all - this can stop the furnace from heating the house, and if left too long can end up with breaking the system itself.

How Often To Change Air Filters

There are several variables that will help you determine how often to change air filters in your home. One of the most important ones is simply the kind of air filter you have. There are two main types of air filters that are used in homes: fiberglass filters and pleated filters.

A table showing information on how long to leave air filters under different conditions

How Often To Change Air Filters: Fiberglass

Fiberglass air filters are the cheaper alternative to pleated air filters, and some landlords prefer them because they are inexpensive and they allow for greater airflow through the vents than pleated air filters do.

The thing is, the supposed benefit of easier airflow in fiberglass air filters doesn’t really make a solid difference in the long run. A working HVAC system shouldn’t have any problems circulating air as long as the filters are fresh.

Fiberglass filters are flimsy, and the same porousness that lets air through also allows dust and other small particles like dirt and pollen. There are many causes of indoor air pollution, and the truth is that fiberglass filters aren’t really robust enough to protect you from all of them.

Fiberglass air filters should be changed every 30 days. Their small surface area means they clog up quickly, and because they are so breakable they are in danger of breaking down and getting parts stuck in your system if they are left too long without being changed.

How Often To Change Air Filters: Pleated

Pleated air filters are better-quality than fiberglass air filters in both material and design. The accordion-like look of the pleated filter material increases its surface area and means that it can catch more dirt and debris before becoming too clogged.

When it comes to how often to change air filters like this, the general rule is to swap out for a new one every 90 days.

There are an array of factors that should be taken into account, though:

Change Your Air Filter More Often If

You Have Pets

This is perhaps the single most important factor in how often to change air filters. An animal constantly shedding hair, tracking in dirt, and producing dander will substantially increase the work your air filter has to do. 

This doesn’t apply so much to smaller pets like guinea pigs or hairless pets like fish. But if you have a dog or a cat who lives indoors, your air filter is going to clog up much more quickly. If you have a pet, you should change your pleated air filter every 60 days.

You Have Allergies Or Asthma

There’s nothing worse than having allergies flare-up in your own home! If you are particularly sensitive to air quality, you’ll want to change your air filter more frequently. When you are planning how often to change air filters, it may be a good idea to change your filters in the springtime if your allergies are pollen related. This will help you to keep your home clean and comfortable. If you have strong allergies or asthma, change your air filter every 25-35 days.

You Have a Large Home

If your home is large and spacious, it’s common sense that your HVAC system has more air it needs to filter. Your air filters may fill up more quickly than they would in a smaller home, so it’s best practice to change them every 60 days.

Your Neighborhood Is Highly Polluted 

If you live in an area with higher air pollution, this will translate to more dirt, smog, and smoke being cycled through your filtration system. If you’re wondering how often to change air filters if you live in a big city, a busy area, or near a highway, it’s best to change it every 60 days.

Final Thoughts

So, there you have it. Hopefully, this has helped you decide how often to change air filters to keep your air fresh and your HVAC system working smoothly. Keep swapping them out every couple of months and you should be just fine.

The freshest filter in the world won’t help your HVAC system do its job if the vents are clogged. Get in touch for your free vent-cleaning consultation today!