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Original message

RPFINGSTEN

205.188.117.9

"filters" , posted Sun 12 Oct 14:29user profileedit/delete messagepost reply

Hello guys... got a question for you about air filters. I recently had to have 2 new heat pump systems installed at my home. When the contractor was finishing up he noticed some filters I had in the closet with the air handler. The pleated filters were very expensive, about 15 to 20 bucks a pop. The contractor told me NOT to use those filters saying they were too restrictive with regard to air flow. He suggested staying with a pleated filter and one that had a merv rating of about 8. When I went to the home depot tonight to buy the new filters I was pleasantly surprised to see that these were only about 3 or 4 bucks each. But my concern is : how can a filter that isn't as effective as the more expensive filters be "better" for my hvac systems. After all these new puppies are brand new and for what I paid to have both installed, I want to make darn sure I'm doing everything I can to keep them operating at peak efficency. Your thoughts? Thanks for the input.

Roland

 


Replies:

ampulman

68.83.78.41

"Re(1):filters" , posted Sun 12 Oct 16:06user profileedit/delete messagepost reply

I'm assuming that we're talking about 1" filters.

Some of the 1" pleated filters sold at the big box stores Are in fact, restrictive.

The key is the total surface area of the filter, not the MERV rating. The MERV rating applies to the porosity of the filter media. A higher MERV rating will involve a lower porosity (hence, somewhat lower airflow), but that can be overcome with greater surface area (number of pleats). You need to check both factors.

You might want to check the internet.

AM

 

ampulman

68.83.78.41

"Re(1):filters" , posted Sun 12 Oct 16:05user profileedit/delete messagepost reply

I'm assuming that we're talking about 1" filters.

Some of the 1" pleated filters sold at the big box stores Are in fact, restrictive.

The key is the total surface area of the filter, not the MERV rating. The MERV rating applies to the porosity of the filter media. A higher MERV rating will involve a lower porosity (hence, somewhat lower airflow), but that can be overcome with greater surface area (number of pleats). You need to check both factors.

You might want to check the internet.

AM

 

 

Freon

74.243.106.133

"Re(2):filters" , posted Tue 14 Oct 16:36user profileedit/delete messagepost reply

Take the size of the AC condenser (in tons) and multiply it by 400. That will give you an approximation of the total air flow needed by your duct system(in cubic feet per minute). Now divide that total cfm by 2 and that will give you an approximation of the total filter area you need. A 2 ton AC system needs ~800 cfm of air and that indicates at least 400 sq in of filter area (20"x20"). More filter area is always better, assuming the return ducts are big enough too. A MERV 6 or 8 will get almost anything that could cause problems with your evaporator coil. Unless allergy problems are a concern, you don't need to over-filter... read the labels and you decide.