The Dirt On Expensive Furnace Filters

By
Home Inspector with Structure Tech Home Inspections

 

Are super expensive furnace filters really worth the extra money?

Ultra Allergen FilterThe 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 anecdotalevidence 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.

StanleyAt 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.

 

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Re-Bloggged 2 times:

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  1. Dan Edward Phillips 03/27/2011 12:03 PM
  2. Maureen McCabe 08/05/2011 11:42 AM
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Rainmaker
196,974
Jim Mushinsky
Centsable Inspection

Interesting reading on your choice for a furnace filter.

I use a more restrictive filter and change it every 2-3 weeks.  I also add a spray coat of disinfectant.  I've been thinking about adding a UV light yet I'm concerned about degradation with dust. 

Do you have any experience with UV in the ducts?

March 17, 2011 03:36 AM
Rainmaker
229,441
Reuben Saltzman
Minneapolis Home Inspections
Structure Tech Home Inspections

Hey Jim, I don't have any personal experience with those UV lights, but my dad had one installed at his own house, and he thinks it might help. 

March 17, 2011 05:52 AM
Ambassador
1,042,547
Charles Buell
Seattle Home Inspector
Charles Buell Inspections Inc.

Reuben, I think the biggest issue with these filters is two fold:  the amount of air that can get around them due to poor restraint and not changing them often enough.  If you take care of both of these issues the cost is not so much a factor.

March 22, 2011 07:50 PM
Rainmaker
555,348
Chris Smith
South Simcoe, Caledon, King, Orangeville Real Esta
Re/Max Chay Realty Inc., Brokerage

Good post, I find that changing a less expensive filter more often is more effective also.

March 27, 2011 01:43 PM
Rainmaker
136,058
Steve Stenros
CREIA MCI, ICC, Home Inspector,San Diego
Poway,La Jolla,Del Mar,Mira Mesa,Carlsbad,Escondido,Temecula

I agree, Reuben. A simple air filter is much healthier for your heating/cooling system! Beware of all the marketing that goes on!

August 05, 2011 11:47 AM
Anonymous
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Rainmaker
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Reuben Saltzman

Minneapolis Home Inspections
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