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rosy
AC filters

Hi folks, what are your thoughts on having 2 ac filters- one at the bottom of the ac box inside the house & one below it a few inches away behind a wall grill-- Would having 2 filters cause the ac to work too hard or would it increase the electric bill? Thanks.

dj1
Re: AC filters

Having two filters is a bad idea.

If it were a good idea, don't you think that equipment manufacturers would have recommended it?

Moreover, using a thick filter, one of those $25 filters which advertise to stop allergies, is the equivalent of hooking a trailer to a small car like smart for 2.

So what filter to use? I use the thin filters that cost 99 cents and REPLACE THEM ONCE A MONTH. I also clean and vacuum the dust in the area where the filter is located.

keith3267
Re: AC filters

Agree with only using one filter, disagree on the allergen filters. You will find that while, per square inch of media, the allergen filters are more restrictive, the allergen filters have many more pleats that are closely spaced. If you unfold all the pleats in an allergen filter, you will find that it has 3-4 times (or more) the filter surface area of the cheap filters. However, I'm not sure the allergen filters are all that effective unless the house is built really tight and the duct system is very well sealed up.

A. Spruce
Re: AC filters

I have used a double filter system, and it worked quite well. I do want to emphasize what the others have said about restriction of air flow, it is a bad thing.

In my situation, I had a furnace with an intake at floor level in a high traffic and high dust/debris area. In this location I installed one of those cheapy, blue "wooly" type filters that have zero restriction and are only good for catching rocks, gravel, and small children from entering the duct. In the furnace itself, I used pleated filters to catch all the dust and smalls that the primary missed. I had good luck with this, with no detriment to the system.

dj1
Re: AC filters

In addition:

The only situation where I would have two filters: when I have two returns with filters mounted right there.

The key is to change the filter on time.

Most a/c failures are the result of dirty filters.

If you have a tenant, go and replace the filter yourself, because some tenants will remove the dirty filter and leave the system filter-less. You don't want that.

HoustonRemodeler
Re: AC filters

Replacing the HVAC filters for your tenants also gets you into the apartment once a month to see what's going on

dj1
Re: AC filters
HoustonRemodeler wrote:

Replacing the HVAC filters for your tenants also gets you into the apartment once a month to see what's going on

Believe me, I don't want to see the tenants' homes and their possessions inside, But I do care about the a/c equipment, so I zoom in n out.

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