AC Filtration Questions

nemo · 03-16-14, 10:26 AM

My AC unit has a electronic air cleaner. The unit seems to work fine trapping dust as the coils stay clean except for cat fur. The cleaning unit consists of a prefilter and the electronic unit. Without affecting the efficiency of the AC can I add another filter? Is there any easy way to determine if the this would create to much restriction? Would it be best before or after the cleaning unit?

Yea I know, get rid of the cat.

doug30293 · 03-16-14, 01:39 PM

If the pre-filter isn't catching the cat hair then it isn't doing its job. If it is a non-woven fiber media you might try replacing it with a cheap pleated filter. Fiber pre-filters are really only good for lint.

My parents had an electronic filter installed to reduce dust. The installers removed the main filter which resulted in even more dust - and cat hair - blowing through the system. I installed a large (24 X 30) filter box at the return air grill and the problem went away.

Just don't make the mistake of getting a high dollar MERV-12 filter thinking it will be even better. Fine filtration elements cause excessive pressure drop unless you substantially increase the total filter area. The first 24 X 30 filter I installed had so much pressure drop it collapsed the return duct. And this was only a 2 ton unit.

ecomodded · 03-17-14, 02:01 AM

I agree if the cat hair is making it onto the Coils then the filter is not doing its job.

I would add more filter material to the edges to enclose the airstream better or buy a larger Pre-filter of similar material and install it so it Fills the air flow completely.

If it was me I would add filter material to the sides and edges.

nemo · 03-20-14, 05:25 PM

Thanks for the feed back. I think the first step is to try to figure out how it got there. Can see it going around the filter. If that doesn't work may remove prefilter and just use a pleated in the return which is already been customized for a tight fit.

03-16-14, 10:26 AM	#1
nemo Lurking Renovator Join Date: Nov 2013 Location: us Posts: 7 Thanks: 0 Thanked 0 Times in 0 Posts	AC Filtration Questions My AC unit has a electronic air cleaner. The unit seems to work fine trapping dust as the coils stay clean except for cat fur. The cleaning unit consists of a prefilter and the electronic unit. Without affecting the efficiency of the AC can I add another filter? Is there any easy way to determine if the this would create to much restriction? Would it be best before or after the cleaning unit? Yea I know, get rid of the cat. Last edited by nemo; 03-16-14 at 10:28 AM..

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03-16-14, 01:39 PM	#2
doug30293 Too Many Projects Join Date: Nov 2013 Location: georgia Posts: 91 Thanks: 0 Thanked 6 Times in 6 Posts	If the pre-filter isn't catching the cat hair then it isn't doing its job. If it is a non-woven fiber media you might try replacing it with a cheap pleated filter. Fiber pre-filters are really only good for lint. My parents had an electronic filter installed to reduce dust. The installers removed the main filter which resulted in even more dust - and cat hair - blowing through the system. I installed a large (24 X 30) filter box at the return air grill and the problem went away. Just don't make the mistake of getting a high dollar MERV-12 filter thinking it will be even better. Fine filtration elements cause excessive pressure drop unless you substantially increase the total filter area. The first 24 X 30 filter I installed had so much pressure drop it collapsed the return duct. And this was only a 2 ton unit.

03-17-14, 02:01 AM	#3
ecomodded Supreme EcoRenovator Join Date: Sep 2012 Location: Vancouver Island,Canada. Posts: 1,037 Thanks: 116 Thanked 100 Times in 87 Posts	I agree if the cat hair is making it onto the Coils then the filter is not doing its job. I would add more filter material to the edges to enclose the airstream better or buy a larger Pre-filter of similar material and install it so it Fills the air flow completely. If it was me I would add filter material to the sides and edges.

03-20-14, 05:25 PM	#4
nemo Lurking Renovator Join Date: Nov 2013 Location: us Posts: 7 Thanks: 0 Thanked 0 Times in 0 Posts	Thanks for the feed back. I think the first step is to try to figure out how it got there. Can see it going around the filter. If that doesn't work may remove prefilter and just use a pleated in the return which is already been customized for a tight fit.