Should You Clean Your HVAC Filter Or Just Replace It?

Sep 28, 2021

HVAC filter and blue brush in the sink.

There are lots of good reasons to change or clean your HVAC filters - be they furnace or AC filters - regularly. A clean filter will help your furnace or AC last longer. Filters also keep airborne contaminants out of your lungs - that’s important for everyone, but it becomes especially important if you have allergies.


We could go on about the benefits of a clean filter - but that’s not the topic of the day. We’re here to talk about how you should clean your filter - more specifically, whether you should clean it, or replace it.


This topic has a surprising amount of depth to it - we’ll need to talk about the type of filter you’re using, how long you’ve been using the filter, and the quality of the filter. That’s a lot to cover, and we tried not to filter out any important information - so let’s get started.


Disposable filters can’t be washed


Let’s start with what might be the most important thing to know: you cannot wash disposable filters. It’s right there in the name - they’re not made to be reused. 


Disposable filters are made out of materials like cardboard and paper that don’t stand up well to washing. In fact, washing disposable filters can lead to more contaminants, as mold can grow on the filters once they’ve been dampened. Obviously, that’s not what you want circulating through your home.


A quick note - our society tends to think of “disposable” as “inferior”. That isn’t the case with disposable filters, as we’ll discuss in the section about filter quality. They can’t be washed, but some disposable filters do an excellent job filtering out particles.


Most disposable filters will last for about one season, or 90 days. Homes with pets or allergy-sufferers should consider cycling through filters more frequently - around once every month or two. 


Throw away worn filters


If your HVAC filter isn’t disposable, then it’s washable. Reusable air filters are becoming more common - and they can last for a very long time.


You want to wash your reusable filter on a regular basis - while you can get away with washing it about 3 times a year, we recommend washing it at least once a month.


Why? Well, for starters, it takes next to no time. You can use the hose attachment from your vacuum to suck up any dust. For a lot of build-up, all you have to do is let the filter soak for about an hour in a bucket of hot water/vinegar mixture. And if it’s warm enough outside, you can just spray the filter down with your garden hose!


Of course, all the spraying and vinegar solutions in the world aren’t going to mean a thing if your filter is damaged. When there are tears, holes, or other structural damage, you’ll need a new filter.


How long do reusable filters last? A very long time. Some air filters can last 10 to 20 years with proper care - some manufacturers even claim their filters will last longer than your furnace or AC unit.


Pretty impressive. 


Cleaning restores quality - it doesn’t improve it


Do you know our friend MERV? MERV is an acronym - it stands for minimum efficiency reporting value. Why such a vague acronym was used, we’ll never know. Fortunately, we’re here to tell you what it means.


A MERV rating tells you how effective a filter is at trapping particles. The higher the MERV rating a filter has, the smaller the particles it can capture.


This is where some disposable filters - specifically, pleated disposable filters - absolutely shine. You can often find disposable filters with MERV values of 10-12, which can catch anything from pet dander to smoke.  


Reusable filters, on the other hand, tend to have much lower MERV ratings - while we’ve seen MERV 9 reusable filters, they are few and far between.


That means you might want to toss out your reusable filter, and opt for a disposable one instead - a bit less cleaning, and much better for pet owners and allergy sufferers.


You may be wondering why there aren’t better reusable filters on the market - we hope they show up soon because they’re much better for the environment. Construction of these types of filters is particularly challenging. There are also basically no HEPA filters for residential HVAC units.


Why? Because while a denser filter catches more particles, it also makes it difficult for your furnace or air conditioner to force air through to your home. HVAC systems are complex!


Keeping your filters clean


Want to limit how often you need to clean or replace your filters? Here are a couple of steps we recommend that you take.


First, the importance of HVAC maintenance can’t be understated. By regularly getting your ducts cleaned, you can limit the amount of work your filter - and your furnace or air conditioner - has to do. Regularly cleaning around your HVAC unit to stop it from drawing in dust is also a good idea.


Second, you’ll want to keep your home as free of dust as possible. If you don’t have time to dust regularly, consider hiring someone to help! Businesses use office cleaning services to keep their HVAC system free of contaminants - homeowners can do the same. 


Keep your air clean and healthy


Whether you opt for reusable or disposable air filters, proper care does a lot to keep your air clean of contaminants. It’s a simple step you can take to prolong the life of your HVAC units and stay healthy - we’re glad you’re looking into it.

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