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#75: 04-20-2012, 05:45 AM
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Originally Posted by seiyafan View Post
Then I think I found the right guy for this question. How is the air flow different for the same filter with same MERV rating but different thickness? Say 1'' pleated vs 2'' pleated. Is it similar, or drastically reduced at 2''?

And also, I bought Accumulair MERV 13 for my office HVAC system the other day because it is cheaper than the Filtrete 2200, but I am not sure which one has higher air flow, do you have any opinions on a good 1'' filter?
Filtrete 2200 is declared MERV 12, Accumulair MERV 13. For Filrete 1900 I found no declaration. Looking at my previous post, You'll see they both are medium-efficiency filters (10 vs. 6-7 micron).

Permeability: is a lab number on a given surface. Example:
- filter "A" is MERV 12 and has 100 m3/m2/h at 200 Pa
- filter "B" is also MERV 12, but has 150 m3/m2/h at 200 Pa => lets 50% more air go through at the same resistance (200 Pa)

Making a flat filter with the same surface (e.g. 1 sqm), "A" will pose more air resistance than "B". Simple conclusion.

But if me make pleated filters, You may put more pleats, or make a higher pleat height, in order to pack more sqm in a given space.

Let's assume this comparison, just as an example:
- a pleated filter made of media "A" with 3 sqm of densely spaced pleats
- a pleated filter made of media "B" with 2 sqm of widely spaced pleats
=> both will have the same air resistance in the end (OK, this example is not without limits, but good just for comprehension).

Coming to Your question:
1) filter 12" x 12" x 1" with 100 pleats media X
2) filter 12" x 12" x 2" with 100 pleats media X
=> 1) will have roughly 50% of filter surface of 2)
=> 1) will have the same air resistance as 2) with 50% of air flow or
=> 1) will last 50% against 2) under the same time/dust-loading cycle (and only in case the ventilator can keep up against its higher air resistance).

Hope to have cleared something....

Last edited by michelino1968; 04-20-2012 at 05:59 AM..