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Furnace Filters

Do high efficient furnace filters (MERV ratings of 8 or higher) make furnaces work harder to pull air into the system? HVAC professionals told me that high MERV rated filters can cause early breakdown of furnaces.

Bob Gabrilson
Re: Furnace Filters

Yes, hi-eff. filters (can) reduce airflow and increase the operating cost. Generally, this is because it's only (one) part of the airflow issue. Most systems are short on return to begin with. Also, I like to oversize the filter if going with a one inch filter. Most four inch pleated filters are already 20X25.

Re: Furnace Filters

Not all high efficient furnace filters. Ask your HVAC installer to recommend one that works well with your system. They don't cause systems to wear down too fast. We sue high efficiency furnace filters (about 2 years) and haven't experienced any problems.
Find licensed HVAC contractors in your area.

Bob Gabrilson
Re: Furnace Filters

All high efficiency (pleated) filters will increase the pressure drop. Will the consumer (without testing) know this? NO.
If you have cancer and choose to ignor it, will it not kill you?

Re: Furnace Filters

You have to remember that your blower motor is rated for a certain no. of amps and a pleated filter while being able to collect more crap could raise the amperage and over time burn it out. Also while running your A/C system it won't move as much air and could give you less of a temp drop. If you don't change the pleated filter on a regular basis and it gets to plugged up you could also end up with a frozen coil. Some thing that is less likely to happen with the green or blue throw away type. I personally don't care for the pleated filter because of these reasons but the choice is the homeowners. Good Luck!!!:)

Bob Gabrilson
Re: Furnace Filters

I could not have said it better. :)
My competition thinks that the "variable-speed" blowers solve all of these issues (airflow) that we discuss here.
The December issue of "the News" had a outstanding artical on blower motors. Page 18, "comparing motor technologies". Enjoy.

Re: Furnace Filters

I agree with Sten and Bob.

It all depends on the air handler --- using a higher Merv can actually reduce the performance of air flow and can over amp the blower motor.
In most cases a filterof around Merv 6 is generally fine enough and doesn't restrict the air flow too much.

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