Saturday, April 4, 2009

Do 3M Furnace Filters Really Work?

  • Are you electric bills too high?
  • Is your 2nd level too hot in the summer?
  • Does your furnace sound really loud?

You can't go to Home Depot, Target, or any other store without seeing 3M filters for sale. Millions of these filters are sold every year. If customers only knew how much money they are really wasting. 3M isn't the only one; ArmHammer, Bluedot, Honeywell, and many others included.

Yes the 3M will catch more dirt than your $3 filter. But they do not let air through either. A furnace duct system efficiency is measured in Static Pressure (SP). Average duct system should create .5" SP across a furnace. The higher the number the harder the furnace blower must work. Out of the .5" allowed, the filter should be about .1". 3M filters commonly have a .25 to .4" SP drop. Basically SP is like your blood pressure. As you know high blood pressure is bad, same with SP.
I have seen furnaces needing to be replaced after only being 6-7 years old commonly. And a huge part will be poor duct design and 3M filters. There are multiple grades of 3M filters also. As the price is higher they are even worse. I think it is purple package can be up to $12-15 each filter and these must be changed even more than the red box.

Think of it this way. The object of 3M filter is catch a lot of dirt and pollen. So it needs really small holes. The problem is the filters are to small to hold all the dirt. When you have a larger media filter they are 4 or 5" thick and can hold more dirt and let the air through.

When you use a 3M filter it is like your furnace running a marathon with a rope around its neck. The furnace can't breath... Which causes over heating in the summer and over cooling in the summer.
Over cooling the a/c in summer will cause the indoor coil to freeze like a block of ice. Next thing you know water is leaking from your furnace and your house gets hot. Plugged air filter is a very common service call Cooling Contractors have in the summer. Once the coil start to freeze up you can also ruin the compressor in the a/c which will commonly cost $1,200 to 1,800 to fix.

In the winter that 3M filter will cause low air flow across the furnace heat exchanger. When that happens the metal in the heat exchanger heats up and cools down more than normal. Then the metal can crack just like if you flex a paper clip to many times. A cracked heat exchanger in a furnace can allow carbon monoxide to leak into the home causing major health effects or even death.

There are many better filter options available. If you are worried about allergies or indoor air quality contact a local HVAC company. If you just want to keep your furnace running for a long time you are better off using the $3 filter instead of the overpriced 3M filter that will just cause you high electric bills and isssues with your heating and cooling equipment. DO NOT follow the 3M instructions either that say change upto 90 days. If you don't want to keep using 3M atleast make sure you change it every 30 days. (some homes even more often)

I like Poly fiber filters for a low cost option. They will cost you about $3 each, you replace them every month and you will be much better off. You can get a low cost filter at just about any hardware store. The best thing to do is talk to your local heating professional about filter while he is at your home doing an annual furnace and A/C cleaning.

In Short
  • Change standard 1" thick filters every 30 days
  • High resistance filters (3M) will drastically increase electrical use
  • If you ever see water leaking by your furnace in the summer, good odds your filter is plugged or just not letting enough air through
  • Use whole house media filters like Trane 5" Perfect fit media
  • Not changing air filters enough will cut the life of your furnace in half


  1. Many people believe that there is only one purpose of a furnace filter or an air conditioning filter. And that is, to reduce dust is in the home. This may be a very important job for your furnace to take on but it's not the only function it has.

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  2. It was worthy knowing that are actually several types of furnace air filters. It would have better if the advantages and disadvantages of each type were discussed.

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  3. Before I read this article, I really don’t have any idea about furnace filters. This article really provides substantial information about the subject matter.

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  4. Thanks for this great article. I have read all information which you have wrote here and very useful tips about for people who are planning to buy Furnace Filters.

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  5. Changing your furnace filter might more of a hassle than it is worth, but in reality, your heater's filter is a very important piece of household property.

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  6. High efficiency furnace filters are no doubt effective, but since they can lead to substantial increases in your electricity bills, you just can't afford to install them as part of your centralized heating and cooling system.

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  7. Furnace air filters are designed to remove unwanted dust, pollen and debris from your heating, ventilating and air conditioning system (HVAC). They also increase the system's productivity by regulating the amount of airflow within the system.

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  8. Furnace filters are needed to keep away particles that will affect you and your family's well being. Clean air is essential in maintaining the health of your family at home and a high quality furnace filter does that for you.

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