The Dirt On Expensive Furnace Filters

Are super expensive furnace filters really worth the extra money?

The main job of a furnace filter is to keep big stuff from getting in to the furnace's heat exchanger or the air conditioner's air coil and clogging things up with dust, pet hair, and other big stuff.  They're not intended to purify the air you breathe.  Furnace filters protect equipment; not people.

Manufacturers of furnace filters would have you believe otherwise (big surprise).  The most expensive disposable filters that I commonly see are the Best 1" Air Filters made by 3M. These filters are marketed as being able to

"help attract and capture allergens from the air passing through the filter including mold spores, pollen, pet dander, dust, smoke, smog particles and particles that carry bacteria and viruses."  

Sure.  I'll buy that.  I'm sure these filters do a great job of preventing all those things from passing through the filter. There is no claim made, even by 3M, to improve indoor air quality.  Up until recently, these filters were sold as "Ultra Allergen" filters, but they've recently changed their wording.  I don't know when this change happened, but I'm sure it was quite recent – you can still purchase "Ultra Allergen" filters on Amazon.

If you want to improve indoor air quality, try something else.  Expensive furnace filters have been proven to have a very small effect on indoor air quality.  There is plenty of anecdotal evidence out there that says expensive filters will solve all of your indoor air quality problems, but I haven't been able to find a single study backing these claims.

The problem with expensive furnace filters is the amount of air flow that gets restricted when they get dirty.  As I mentioned in my blog about the importance of changing your furnace filter, reduced air flow can actually lead to premature failure of your furnace, besides costing you more in heating bills.  This can also lead to service calls on your furnace.  Furnaces come equipped with heat sensors that will shut the furnace down if the heat exchanger gets too hot, and the main cause of this is insufficient air flow.

Stanley At my own house, I use a cheap pleated filter.  It's reinforced with steel wire on one side and will last for up to 90 days.  I have a German Shepherd (Stanley) who sheds like crazy, so I change my filter a little more often – about once every 60 days.  I don't like the super-cheap fiberglass filters because they seem to let too much stuff through, and I'm concerned that the air coil would get gunked up with all that dust that would still come through.  

My recommendation is to skip those super-expensive furnace filters.  I think they're a waste of money.

Reuben Saltzman, Structure Tech Home Inspections - Email - Maple Grove Home Inspections

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Reuben is a second-generation home inspector with a passion for his work. He grew up remodeling homes and learning about carpentry since he was old enough to hold a hammer. Reuben grew up thinking he was going to be a school teacher because he enjoyed teaching others so much. In a sense, that’s a lot of what home inspections are about, so Reuben truly does what he loves. Sharlene has worked with Structure Tech since 2000 and Reuben has been contributing to her blog since 2008.

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