# Furnace filter brands to avoid?



## beenthere (Oct 11, 2008)

They are too restrictive.

Use a general pleated filter. MERV 8 at most.
Don't use any of the electrostatic air filters. They are also too restrictive.


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## yuri (Nov 29, 2008)

Merv 8 or 10 is good. But you should have a tech check the air temp rise thru the furnace if using a Merv 10 and change it regularly. The replacement media for those plug in electrostatics is ridiculously expensive and the unit breaks easy. We stopped selling them. The other washable type are difficult to keep clean and I doubt if you can ever wash them back to as clean as new. 3M rates theirs in microns which is not illegal but confusing as the industry standard is MERV.
http://www.filterair.info/articles/article.cfm/ArticleID/7AF95A61-EAF8-4C90-BFA98EE04B0DD02B

google:merv


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## MistyLee (Nov 9, 2009)

Thank you both. I will get a pleated type. Regarding the electrostatic ones to stay away from, is that just the permanent ones to avoid? Are the disposable pleated electrostatic acceptable?


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## yuri (Nov 29, 2008)

There are 2 types of "electrostatic" filters. The permanent washable type which are restricitive and impossible to get totally clean. They supposedly use the air passing thru their special material to create a electrostatic charge. I have never found them to work very well and they are difficult to keep clean. The plug in type uses a small electric power transformer and a thin wire to the filter to energize it. The replacement membrane/pad is very expensive, the power connection breaks easily and they are restrictive. Disposable accordion type filters are the best.


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## MistyLee (Nov 9, 2009)

I am planning to get a pleated type with a 7 or 8 MERV, but the details of the Kimberly Clark brand indicates the pleated style is electrostatically charged. Is that okay for a disposal filter?


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## yuri (Nov 29, 2008)

"Electrostatically" is nothing more than a clever marketing buzzword to charge more $$ to unsuspecting consumers. 3XX brand is very good at that. Static electricity occurs when it is dry and you rub your feet on carpet, how can they "charge" a paper filter? Just like "new and improved". The MERV rating is all you need.:thumbsup:


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## MistyLee (Nov 9, 2009)

Thanks for the info. The brand I was looking at was a Kimberly Clark pleated style which is formulated from some type of synthetic material. I didn't necessarily want the "electrostatically charged" feature, but apparently it comes with that feature. I am hoping the MERV 7 rating will not have too much of a "pressure drop" since it is going to be installed in a furnace as an alternative for a permanent type which I assume would normally have a very low pressure drop. There sure seems to be a lot of detail involved in furnace filters. I just don't want to damage a new furnace.


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## carollbert (Oct 28, 2015)

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.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. if you planning to replace a disposable furnace filter with a permanent washable electronic type you can go any brand.


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## mkretsinger (Nov 6, 2015)

3M makes a good filter as long as you choose one that is not too restrictive for your air handler. In my personal opinion, the electrostatic filters are great in the short term, but they lose their "static quality" over time and never really regains the factory qualities. Making them a terrible choice in my opinion.


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## mkretsinger (Nov 6, 2015)

As a follow up ... the only problem I have with 3M filters is that they are terribly expensive. Personally, I buy Purolator Air Filters. The pleated filters are the same MERV rating and are much cheaper than the 3Ms. The only problem is you have to buy in bulk and wait for delivery. But, if you plan it right, you can buy a year's worth for much cheaper than having to run out to the store at the last minute and paying up to $25 each.


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