The Dirt On Expensive Furnace Filters

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.



Re-Blogged 2 times:

Re-Blogged By Re-Blogged At
  1. Dan Edward Phillips 03/27/2011 05:03 AM
  2. Maureen McCabe 08/05/2011 04:42 AM
Home Improvement
Ask the Home Inspector
Home Inspector's Corner
Professional Home Inspectors
Minnesota Real Estate
furnace filters
are expensive furnace filters worth it
what are furnace filters for
purpose of furnace filters
what type of further filt

Post a Comment
Spam prevention
Spam prevention
Show All Comments
Scott Petersen
Client First, Realtors - Canton, MI - Canton, MI

My HVAC guy has told me the same thing. Save your money on the super extra filters.

Mar 15, 2011 04:50 AM #26
Donald Hester
NCW Home Inspections, LLC - Wenatchee, WA
NCW Home Inspections, LLC


Great advice. I have talked with HVAC techs on this. It seems that most say go with the higher flow rate for the performance of the system. I had an issue with my filters restricting the airflow enough to caused some major icing during the AC  usage. Once I put the cheaper filter in and more airflow it reduced this.

Mar 15, 2011 05:26 AM #27
Ilyce Glink
Think Glink Media - Chicago, IL
Best-selling author, award-winning TV/radio host.

Thanks for the advice. Reuben. More evidence that even high-end products don't replace actual work-change your filters often and don't worry about getting the fancy stuff.

Mar 15, 2011 05:59 AM #28
Chris Alston
Chris Alston (Keller Williams Realty, Silicon Valley, California) - Campbell, CA
Silicon Valley, California

Great advice...  I have often wondered about this very same thing!

Mar 15, 2011 06:00 AM #29
Jack Tenold
Caliber Home Loans, Inc. NMLS 15622 - Spokane, WA
Conventional and Reverse

My furnace uses 2 filters (which I didn't realize for quite some time).  I always changed one and didn't even know there was another one on the back side.   Maybe other readers need to double check -- 2 filters or one?  When they go on sale at my hardware store, I stock up so I always have extras.....saves money and reminds me to replace them. I always thought the purpose of the filter was air quality and not furnace equipment protection.  Never too late to learn.

Thanks Reuben for the valuable information.

Mar 15, 2011 06:58 AM #30
Karen Baker
Sunset Beach and Beyond Realty - Sunset Beach, NC
Professional Help with Rapid Responses...

Reuben ~ That was certainly the best advice I have ever heard about filters ~ Cheap pleated reinforced with steel wire on one side ~ will check these out ~ Thanks for the dirt!!

Mar 15, 2011 08:27 AM #31
Barb Van Stensel
Chicago, IL

A lot of pros and cons on filters but I am definitely for the ones that work vs the price and false promises.  Save the motor, keep your health in shape and change the filter often.  Good reminder for those who do not change the filter too often.

Mar 15, 2011 08:46 AM #32
Diane McDermott
Realtor®, GRI, Landis e2 Real Estate, LLC - Charlotte, NC
Charlotte NC Real Estate Market

Very interesting topic!  I knew to change them and I see enough filthy ones to know that's not exactly common practice in homes,  I usually go for the mid-range, good to know I'm not missing any extraordinary benefits from the more expensive ones

Mar 15, 2011 11:09 AM #33
Kevin J. May
Florida Supreme Realty - Hobe Sound, FL
Serving the Treasure & Paradise Coasts of Florida

Reuben, a 3-pack of pleated filters gets me through a years worth of HVAC activity.  Great points, and rarely, if ever, have I found the filters to be affecting flow upon their replacement.    

Mar 15, 2011 11:24 AM #34
Lyn Sims
RE/MAX Suburban - Schaumburg, IL
Schaumburg IL Area Real Estate

I don't know, I just thru one out today that was pretty fuzzy. I've noticed that the house is dustier without a good filter. That's my stance & I'm sticking with it.

Mar 15, 2011 01:52 PM #35
Reuben Saltzman
Structure Tech Home Inspections - Minneapolis, MN
Delivering the Unbiased Truth.

Lenn - definitely, filters are only good if you remember to change 'em.  You say you're looking for a filter that won't put an extra load on the blower motor... I've heard about UV lights that can be installed in the ductwork.  I don't know much about 'em, but my dad had one installed at his own house.  

Jay - Three or four times a day?  That's sounds about right.  Not a way to clean your air.

Judy - thanks.

Dale - I've given this spiel many times during home inspections.  Now I'll have a link to give 'em.

Irene - good plan.  You might even want to turn your furnace off when heavy sanding is going on.

Christine - lots of people swear by the Ultra-Allergen filters.  If that's what you're using, I would change them more than every 90 days.  90 days is the longest you're ever supposed to get out of the filters; you'd be better off changing them more frequently.  Also, give the inexpensive pleated filters a try to see if you notice a difference.

Michael P - set a reminder on Outlook.

Michael S - No, you probably didn't waste your money on the electronic system.  They do a fine job of removing dust particulates, and you don't have to replace any filters.  They just take a little more work because you need to clean the pre-filters and the electronic cells.

Dennis - I completely agree.

Michelle - I'm glad I could help.

Mar 15, 2011 02:05 PM #36
Reuben Saltzman
Structure Tech Home Inspections - Minneapolis, MN
Delivering the Unbiased Truth.

Patricia - thanks.

Robert - I once saw a guy in his garage with a big pile of furnace filters that he must have taken home from work.  He was blowing them all out with an air hose.  I took a photo of him doing this, but I can't remember where it is.  I'd rather just buy a new one :)

Jody - I don't have any problem with the fiberglass filters, but it's only a little more money for the pleated.

Lizette - I've heard nothing but bad stuff about those washable filters.  I'd go with the disposable.

Christine & Jennifer - me too :)

Debra - glad to help with the argument.

Bill - I was also surprised.  You really gotta read the wording carefully to realize this.

Scott - most HVAC guys I know say they love those super expensive furnace filters... because they create service calls!

Donald - I've seen that same thing happen to people many times.

Ilyce - that's about it.  

Mar 15, 2011 02:12 PM #37
Reuben Saltzman
Structure Tech Home Inspections - Minneapolis, MN
Delivering the Unbiased Truth.

Chris - thanks!

Jack - two filters?  That's quite unusual.  I've seen it before, but it's rare.

Frank & Karen - thanks, glad to help.

Barb - you got it.

Diane - the cheap pleated filters would be considered a mid-range.  It sounds like we're on the same page.

Kevin - you're pushing the limits, but then again, you probably have several months where you rarely need to run the blower on your ... furnace?

Lyn - I'll be looking for the lab reports on the indoor air quality for your house.

Mar 15, 2011 02:18 PM #38
James Quarello
JRV Home Inspection Services, LLC - Wallingford, CT
Connecticut Home Inspector

I'm totally with you on this one. I have never owned or lived in a home with a furnace, but a filters a filter, whatever it filters. The finer the holes, the quicker it clogs. Those super filters also have a reputation for freezing up A/C coils just like you say, by restricting air flow.

Mar 15, 2011 02:33 PM #39
Reuben Saltzman
Structure Tech Home Inspections - Minneapolis, MN
Delivering the Unbiased Truth.

I kinda forgot to talk about iced up AC coils; it's just been such a long time since I've even thought about AC...

Mar 15, 2011 02:58 PM #40
Jim Mushinsky
Centsable Inspection - Framingham, MA

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?

Mar 16, 2011 08:36 PM #41
Reuben Saltzman
Structure Tech Home Inspections - Minneapolis, MN
Delivering the Unbiased Truth.

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. 

Mar 16, 2011 10:52 PM #42
Charles Buell
Charles Buell Inspections Inc. - Seattle, WA
Seattle Home Inspector

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.

Mar 22, 2011 12:50 PM #43
Chris Smith
Re/Max Chay Realty Inc., Brokerage - New Tecumseth, ON
South Simcoe, Caledon, King, Orangeville Real Esta

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

Mar 27, 2011 06:43 AM #44
Steve Stenros
Poway,La Jolla,Del Mar,Mira Mesa,Carlsbad,Escondido,Temecula - San Diego, CA
CREIA MCI, ICC, ACI Home Inspector,San Diego

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

Aug 05, 2011 04:47 AM #45
Post a Comment
Spam prevention
Show All Comments

What's the reason you're reporting this blog entry?

Are you sure you want to report this blog entry as spam?


Reuben Saltzman

Delivering the Unbiased Truth.
Ask me a question
Spam prevention

Additional Information