Heating, Air Conditioning & Refrigeration Wind & Solar

Does a Dirty Furnace Filter Impact the Operation?

Unfortunately, one of the most often neglected maintenance tasks for a homeowner is changing the furnace filter on a regular basis. It’s also one of least expensive things you can do to insure proper performance and longevity of the equipment. The filter pictured below was restricting the air flow so much that the furnace was overheating and tripping off on the high limit switch, leaving the occupants in a cold house overnight!


What happens when your furnace filter becomes totally plugged?

  • Reduced air flow across the heat exchanger resulting in higher heat exchange operating temperatures. This can result in cracked heat exchangers causing CO to leak into the space being heated.
  • Increased run times due to lower air flow. This results in higher fuel costs because it takes longer to heat the space.
  • Blower motors pull higher amps when the air flow is restricted; especially susceptible are variable speed motors. This can shortened the life of the motor.
  • So how often should you change your filter? If you purchase the inexpensive disposable one inch filters at the grocery or hardware store you will probably need to change it every month. The one inch disposable filters that we carry will last in most homes for three months. A four inch high efficiency air filtering system usually requires only once a year changes. Until you become familiar with your own filters expected life, it’s probably a good idea to take a quick look at it on the first day of every month, to insure you are protecting your heating system.