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    Aging Well Partners
  • Aug 03
  • 3 min

The Dirt on Furnace Filters

The Dirt on Furnace Filters

Have you checked your furnace filter lately?  HVAC experts recommend that we change our furnace filters every 3 months.  For those living in areas of the United States that get four distinct seasons, the change of season is a great reminder to change the filter.  Others who live in areas where the change of season is hardly noticeable, you may need to add a note to your calendar.

Find the fresh air intake for your furnace.  This is where you will find the furnace filter.  The filter’s job is to trap and hold the particulate in the air as your furnace pulls air from your home up into the blower fan, heats it and blows it back into the house via the floor or ceiling air ducts.  This cycle of pulling the home’s air into the furnace, heating it, and pushing it back out through ducts is continuous so that filter is constantly working to trap any dirt and dust particles, pet dander, pollen, and other pollutants to ensure the air being forced back into your living space is clean and warm.  When the filter is dirty, it can no longer effectively do this, and your furnace begins recirculating “dirty” air.

All furnace filters are not built the same – the materials used, and thickness of each filter determines how much particulate it will filter from the air and the size of filter needed for your particular furnace – will determine what you purchase.  Your basic spun glass furnace filter is approximately 1 inch thick and can filter larger particulate from the air. These are the lowest cost filter; you can find them at your local hardware store. More expensive filters can filter out 80-95% of particulate from your home’s air while others not only filter the air but kill bacteria and viruses in the air, actually improving your indoor air quality.  If you have pulmonary issues, you may want to consider an electrostatic filter for your furnace.  Ensure you are buying the right size filter for your furnace.  I have replaced many a furnace filter only to find the existing filter had been “shoved” in the space and forced to fit – inefficient and potentially costly as it could have ruined the furnace.  Check the owner’s manual if you still have it laying around for the proper size filter to purchase.  Then head down to your local hardware store (I’d call first to make sure they have the size in stock) and grab yourself a new furnace filter (or 3).  You can also order filters online through Amazon or other online retailers and have them delivered to your door.  When you insert the filter, there will be arrows showing you the direction in which the air should flow through the filter.  Insert the filter with the proper side up, close the filter door, drawer, or grate and breathe easy knowing your indoor air quality just got a whole lot better.

P.S. if all this seems a bit too much, your local handyman or HVAC professional can assist you with replacing your furnace filter.  If you go with the HVAC professional, you may want to have your furnace serviced (which often includes a new filter), especially if you can’t recall the last time it was serviced.


Kie Copenhaver is a Certified Senior Advisor (CSA), Gerontologist, and co-founder of Aging Well Partners. Kie has worked over 25 years in the healthcare and aging industries, advocating for patient’s rights and the ability to choose what’s best for them.  She has taught at Mesa Community College in the Health Information Technology department and currently gives talks at Oasis Lifelong Learning geared towards planning ahead and aging well.  When Kie isn’t working, you can find her doing yardwork and digging in her flower beds.  Find Kie at www.agingwellpartners.com