How Dirty Air Filters Damage your HVAC System

A dirty air filter is something you never want in your home, but it happens from time to time. Air filters are one of those out of sight, out of mind home maintenance tasks. It’s easy to forget that they are there and need to be maintained. Because if they aren’t, you can run into several problems.

Here are a few effects of a dirty air filter that you need to be aware of.

Lower Air Quality
The most obvious problem that comes from a dirty air filter is lower air quality. A dirty air filter is maxed out. It can no longer capture air particles, so those particles pass through the filter, cycling back through the HVAC and into the air you breathe.

Allergy and Asthma Problems
When the air quality drops, problems go up for people with allergies and asthma. Higher levels of allergens and pollutants in the air increase the risk of an allergy or asthma attack.

Reduced Efficiency
When your air filter is dirty, you’ll end up paying more to run your HVAC system. A dirty air filter makes the HVAC system work harder to do its job. As a result, more energy has to be used to keep the temperature constant.

The Worst Problem Caused by a Dirty Air Filter

Of all the problems caused by a dirty air filter, one stands out as the worst. A dirty air filter can harm your HVAC system and cause premature wear because the equipment has to work harder. The problem can get so bad over time that the HVAC system stops working.

Some of the HVAC problems that are caused by a dirty air filter include:

  • Short cycling (turning on and off after just five minutes or so) creates cold and hot spots in your home while also straining the HVAC system.
  • Build up in the ductwork that will need to be cleaned out by an HVAC technician.
  • Blower motor overheating from the air handler has to work harder.
  • Iced over evaporator coils is a serious problem. The low airflow from the dirty air filter causes cold air to get trapped inside the system.
  • System freeze-ups can occur if iced-over evaporator coils aren’t fixed.

The damage isn’t cheap to fix and going without an HVAC system is extremely inconvenient.

a man wearing a fur coat adjusting the temperature of the AC

Symptoms of a Dirty Air Filter

So how do you know if your air filters are dirty? Besides physically checking them out, it can be hard to tell when an air filter is dirty and no longer doing its job. But several symptoms show up when the air filter gets dirty.

Not Heating and Cooling Like Usual
One symptom of a dirty air filter that you’ll notice is the HVAC system isn’t heating and cooling like normal. If you have to adjust the temperature up or down but the weather outside hasn’t changed, then it’s time to check the air filter.

Uneven Heating and Cooling
As mentioned above, dirty air filters can lead to short cycling, causing hot and cold spots in the house.

Short Cycling
The short cycling itself is an indicator that the air filter needs to be checked.

a hand showing the accumulated dust on a dirty air filter

Causes of a Dirty Air Filter

All air filters will eventually get dirty with enough use, and this is by design. Air filters get dirty because of the air particles that are trapped inside. Eventually, after enough time, the trapped build-up particles and the air filter becomes dirty.

There are a few things that influence how quickly an air filter will get dirty. They include:

  • The outdoor air quality
  • How often you naturally ventilate your home
  • The thickness of the air filter
  • The MERV rating of the air filter
  • The air filter type
  • Activity within the home
  • Amount of HVAC use
  • The presence of air purifiers in the home

There are hundreds of sources of air pollution all around us. A good air filter will capture a large amount of it and in the process become dirty.

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The Importance of Keeping Your Air Filter Clean

All of the problems described above can be avoided simply by keeping your air filter clean. It’s not an expensive fix, nor is it difficult to do. Even better is the fact that a clean air filter will improve immediately.

Bottom line: air filters need to be clean to do their job. Dirty air filters need to be addressed right away, and maintenance measures should be taken to keep air filters clean.

How to Properly Maintain Your Air Filter

Air filters require maintenance, just like your other HVAC system components. The maintenance that’s needed depends on the type of air filter you have. There are two basic types: disposable and reusable.

Maintaining Disposable Air Filters
Disposable air filter maintenance is pretty easy since these filters get tossed after they get dirty. But you do have to remember to replace disposable air filters. You’ll need to replace the old, dirty air filter with a new one every 1-3 months.

How soon a disposable air filter needs to be replaced depends on several factors. The thickness of the air filter and filter material type makes a difference in longevity. How much you use the HVAC system also matters. Lifestyle choices are another factor. Most notable is whether there are pets inside the home or someone who smokes.

Maintaining Reusable Air Filters
Reusable air filters are also known as washable air filters because they can be cleaned and reused. You’ll want to follow a similar timeline as with a disposable air filter and clean your filter once every month. After washing, the filter will need to be set out to dry completely before reinstalling it. Eventually, reusable air filters will get worn out and need to be replaced, so keep that in mind.

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Where to Get Air Filters

You know that you need to change your air filters regularly, so the question is where can you get air filters. The short answer is you can get them at just about any home improvement store and online, but you may not find precisely what you need.

Air filters come in a lot of sizes, and there are different types of air filters for specific purposes. If you have an air filter compartment that isn’t a standard size, then it may be hard to find what you need at a big box store.

If you want a large selection of high-quality air filters at the best price possible, then get your air filter from an original manufacturer. You can buy directly from an OM like Filterbuy online and save yourself a trip to the store.

Many customers make the switch to Filterbuy to take advantage of our custom-sized air filters. We can make 1”, 2” and 4” air filters that are up to 50” wide and 60” in length. Air filters can be cut to ⅛” for an exact fit.

Many original manufacturers’ prices are even better than what you’ll find in-store, and you can order in bulk to save more. Plus, you’ll have a clean air filter handy whenever the old one gets dirty.

READ MORE: How Does an Air Filter Work?