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Filters on cold air returns

Posted by pjb999 (My Page) on
Tue, Sep 12, 06 at 19:56

Regular viewers will know at the moment I'm particularly interested in cold air returns, and whilst painting, I've noticed how dusty my cold air ducts are. I plan to get them cleaned (I know, it's controversial) but I can see they're dusty beyond where I can reach with my vacuum.

SInce I have a dog, I'm mindful of the fact the current CARS are floor-level and will vacuum up a lot of dust etc when system's running.

I'm wondering if pre-filters are the way to go. Granted two things - one, if they're not changed or cleaned often, they'll affect the system performance, and also, I doubt they'll be very effective unless I weatherstrip around the edges so all air runs through the filter.

Is this a good idea? Will it, for example, extend the life of the system filter? Will it help keep the ducts clean, once I've had them done?


Follow-Up Postings:

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RE: Filters on cold air returns

And, for that matter. should/can the fresh air inlet to the furnace be filtered?


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RE: Filters on cold air returns

I had my system designed with 1 inch fiberglass filters in every return and an "air bear" filter on AH. Air bear is due for replacement next month, I'll post the results. I can easily see the pet air and smootz that the return filters are collecting.


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RE: Filters on cold air returns

Filters? Must be that time of year to replace the good old hardware store filters that a horse fly can get through.

Here is a link that might be useful: Home Construction Resource


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RE: Filters on cold air returns

Having filters on yor ducts will effect your systems performance. If need be change your regular filter more often 4 times a year maybe.


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RE: Filters on cold air returns

Ok, thanks. Admittedly the filter material I was looking at for the CARs is more of the 'horse fly' variety...ok for trapping gross pollutants I suppose, like the dog hairs I'm concerned about. Certainly I'll be changing the regular filter often, and I've been thinking about the electrostatic type too - the one that looks like a regular filter but has a wire etc running off it, I don't know too much about them....same principle as smokeless chimney I suppose, anode and cathode.

Right now, apres painting, my old basic two wire thermostat's hanging off the wall, it got knocked around a few times. I have a brand-new programmable 5-wire job just waiting for me to pull the new 5-wire cable through, and since the outside temp's down to 9.5C today, I guess it's time to think about getting the furnace ready...


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RE: Filters on cold air returns

Consider placing filter material at the outlets.
There is a blue mesh material we found at HD that
really cuts down the dust particles. Cut and place
the material inside the duct outlet, voila!


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RE: Filters on cold air returns

Thanks Bushleage - what did you do with the edges? Did you add seals? My system's got the returns (I assume when you said outlets you mean the return inlets) partly built into the walls/floor so they don't seal really well, I will have to run some sort of weatherstripping along the edges of the grilles to make it meaningful, or it'll just follow the path of least resistance and draw air 'round the edges of the grilles.


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RE: Filters on cold air returns

to many filters on a system is not a good thing. The system is designed too run with the filter on the return or inlet side of the air handler or furnace. If you add filters on the return air grilles also, that will restrict the airflow even more which could cause problems with the unit freezing up etc.


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RE: Filters on cold air returns

Nothing like filtering the filter's filter so the filter doesn't collect dirt from the filters filter that was filterd.

Now, if I could only filter out what I just typed.


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RE: Changing Filters on cold air returns

I usually have my son change the filters but I'm tired of waiting for him. So I hauled out the ladder and went up to the cold air return. The filter has arrows on it pointing either into the duct or out to the room. Which is the correct way? I assume into the duct as the cold air would be blowing into it. Am I right or wrong? Thanks.

Pat


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RE: Filters on cold air returns

If you add too much additional filter media, you will need additional return registers. This is not normally a good idea. Excess filter media restricts the airflow. It just aint right.


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RE: Filters on cold air returns

Filters are used on the return to protecrt the heat exchanger and AC coil from plugging with dust.
Adding filters that a system was not desiged for can choke air flow and reduce efficiency and even lead to overheating or freeze up depending on the season.
Every system should have at least a filter on the return side before the blower.


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RE: Filters on cold air returns

Just curious if you ever tried this out (sorry to revive a dead post) and what you thought of the results. I have the same issue with a few pets and floor level air return; I took the cover off this morning and it's pretty nasty down there. Would appreciate any further info :)


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RE: Filters on cold air returns

I have an unframed filter with a fuzzy side and a smooth side. Which side faces into the duct? Thanks!


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