My furnace was installed with a 16x20x1 pleated filter.
It looks like there is enough space to fit a 16x20x2 filter. This should last longer and reduce air resistance.
Is there any reason not to?
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15 years ago
is it always better to use a thicker filter in furnace?
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- posted
15 years ago
How can doubling the thickness _reduce_ resistance?
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15 years ago
It doubles the surface area.
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15 years ago
?????
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15 years ago
He did specify pleated. If you can find a 2" thick filter with a single layer of media, he is correct, the surface of the media would be approximately double that of the thinner filter, assuming the same number of pleats and that both filters have the pleat creases at the very outside of the filter.
nate
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- posted
15 years ago
On Wed, 22 Oct 2008 09:36:09 -0700, "Bob F" wrote Re Re: is it always better to use a thicker filter in furnace?:
So if you could rig 4 filters it would reduce the resistance more? And if you could put 8 or 16 filters you could reduce the resistance to almost zero.
I don't think so, unless you rig the filters in parallel.
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15 years ago
And 17 or more filters would reverse the airflow!
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15 years ago
It's the CROSS SECTIONAL area that is important in fluid dynamics. Doubling the amount of material in that CROSS SECTIONAL area will RESTRICT the flow.
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15 years ago
Accordian fold, pleated filters. Look a bit like this, from the side:
V^V^V^V^V^V^V^V^V^V^V^V
So, the double thickness does provide more surface area.
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- posted
15 years ago
Every filter is different, they are rated for cfm and filtering ability. I have a 4" april air that has good flow and filtration, you have to find a rating in cfm, first pass % efficency and probably more to know what you are buying. There are 1-2 " junk and 1-2" very good filters made. How it seals in the case is maybe as or more important since unfiltered air just bypasses with a bad fit.
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15 years ago
The suggestion was to use a single 2" filter instead of a single 1" filter.
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15 years ago
With a PLEATED filter, DOUBLING the thickness increases the SURFACE AREA by about DOUBLE. So, you're actually DOUBLING the SURFACE AREA of the filter, which effectively HALVES the air flow through each SQUARE FOOT of filter material. Thus, PERMITS mroe air flow with LESS restriction.
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15 years ago
Most of the HVAC work me and my brother do is commercial. Every new installation gets 2" pleated filters because they simply work better. Homeowners can have large air filters like Aprilaire Media Air Cleaners installed on their furnace/air handlers.
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posted that they had a problem with Aprilaire filter packs sealing so any installation should be checked thoroughly. There are several different brands of large air filters and you should pick one that has media you can obtain from a local supplier.
TDD
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- posted
15 years ago
Air Bear has a positive tight seal
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15 years ago
Oh yea, I found Air Bear on The Internet.
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TDD
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15 years ago
Keeping the CROSS SECTIONAL area (duct size) constant while increasing the area (what you've called "SURFACE AREA")of filter material in contact with the fluid (i.e., AIR) moving through the duct increases the air resistance (in this case, the VISCOUS drag). QED
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15 years ago
There ya' go...right. I was concentrating on the areas knowing at best it could stay same.
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15 years ago
I was the one that brought up the issue of loading.
Would you agree or disagree that spreading the same amount of dust over twice the surface area would "improve" the air flow over time - by that I mean it would flatten the "degradation of air flow" curve over the life of the filter. Not an actual increase in air flow, but a stronger flow for a longer time due to less restriction.
That's a legitimate question on my part - I'm not trying to convince you of anything, 'cuz i I don't know the answer. It just seems (to me) that the system ought to act that way.
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15 years ago
Parallel. Exactly. The thicker filter is like two thinner ones side-by-side.
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15 years ago
I was the one that brought up the issue of loading.
Would you agree or disagree that spreading the same amount of dust over twice the surface area would "improve" the air flow over time - by that I mean it would flatten the "degradation of air flow" curve over the life of the filter. Not an actual increase in air flow, but a stronger flow for a longer time due to less restriction.
That's a legitimate question on my part - I'm not trying to convince you of anything, 'cuz i I don't know the answer. It just seems (to me) that the system ought to act that way.
*********************************************************8It would do that, and lessen the drop across the brand new filter also.
If you look at the "holes per area" analogy, there are twice as many holes for air to flow through, and twice as many holes to collect the same amount of dust, so they plug more slowly.