What Can Happen if You Don't Replace Your Furnace Air Filter

The question is, how often the air filter in your furnace be replaced and what can happen if you don't replace it at all? Lots of people don’t realize that their furnace has an air filter and what’s important is that you take proper action now to keep the filter replaced on a regular schedule. If you don’t replace your furnace filter regularly you could find yourself without heat or air conditioning, or worse, be required to pay for the repairs due to your lease outlining the requirement to change your furnace filter regularly.

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What Does the Furnace Filter do?

You may wonder why the air filter is important, after all, you’ve gone this long without changing it and the system seems to work just fine. The air filter actually plays a significant role in keeping your furnace healthy and working properly. The furnace filter is installed in the return duct so that all air flowing into the furnace must first flow through the filter first and be cleaned of dust and debris that might otherwise make it into the furnace, which can cause problems. This is why the furnace air filter needs to be replaced every few months.

The Problem of Short-Cycling

If the furnace air filter is not replaced often enough, it will eventually become clogged to the point that air cannot pass through it. When the furnace fan is running, the lack of air flow will trap the heat in the system. As the temperature inside the system continues to rise, the limit switch will activate and shut down the furnace to prevent it from over-heating. This will temporarily mitigate the issue, but it won’t solve the root problem. Without a new air filter, the furnace will overheat every time it starts up again. This is referred to as short cycling and it can wear equipment out and cause it to fail prematurely. And, you will be without heat. You also increase how much electricity you're using which causes a higher than usual power bill.

The Consequences of Not Replacing your Furnace Air Filter

Prolonged short cycling can cause lots of problems for the furnace. The output of the system drops, due to the lack of air flow. The wear and tear on the furnace increases significantly, causing more frequent problems and equipment failures. If the problem is not corrected in time, the lifespan of the furnace could be shortened by years, increased power bills,  increased humidity and a decrease of air quality can result. It's even possible that the electric heating coils could overheat and start a fire. The main problem for a tenant is the system may fail and then you're without heat (or air-conditioning depending on the season), until the system has been replaced or repaired. If you notice your furnace turning on and off every couple of minutes, turn it off and report it to your landlord or property manager immediately. The faster you can get the system repaired, the better.

Helpful Tips

  • Set a reoccurring reminder on your phone's calendar to remind you to change the furnace air filter every other month. This way you don't forget, and  you avoid the problems that can occur with a dirty clogged up filter.
  • Don't buy one filter at a time. Go to big box stores like Walmart or Lowes and buy a pack of six (6) filters at a time. This would equate to a full years of filters if you stay on schedule to change it every other month.
  • Keep bedroom and bathroom doors open as often as possible so that theres a good pathway for air to make its way from the registers (vents in your ceiling or floors) back to the return where the air filter is located. This open flow of air increases air quality, which means cleaner air, better conditioned air which means your home is more comfortable, along with less humidity.
  • Wipe and/or vacuum dust from the furnace housing and louvers each time you change the filter. This ensures that everything is kept clean and least amount of dust is present.
  • While it may sound like a hassle and lots of work, it really only takes a few minutes. Remember, its the air you and your family and pets are breathing and the comfort level of your home that relies on keeping your furnace air filters replaced on a regular basis.

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