FURNACE FILTERS IN COLD AIR RETURN

[Larry-P]

We want to improve our filtering of the furnace output to cut down on more of the dust. I've installed screen door screening on the inside of the stair cold air vents. But this does not seem to be doing as good a job as we would like.
Last year I cut down regular furnace filters and also placed them behind the stair vents but I feel that was too messy for the return I got for my effort.
I'm thinking of placing foam filter material & the screening behind the stair vents to act as a filtering system. My intent is to use washable foam material.
My questions are has anyone done anything along these lines in providing a good furnace filtering system. Also,where would I pickup this type of foam material that would be washable & safe enough for easy air flow.
Thanks in advance for any & all help.

P.S. Merry Christmas to all.................

[CORattler]

quote:Originally posted by Larry-P

We want to improve our filtering of the furnace output to cut down on more of the dust. I've installed screen door screening on the inside of the stair cold air vents. But this does not seem to be doing as good a job as we would like.
Last year I cut down regular furnace filters and also placed them behind the stair vents but I feel that was too messy for the return I got for my effort.
I'm thinking of placing foam filter material & the screening behind the stair vents to act as a filtering system. My intent is to use washable foam material.
My questions are has anyone done anything along these lines in providing a good furnace filtering system. Also,where would I pickup this type of foam material that would be washable & safe enough for easy air flow.
Thanks in advance for any & all help.

P.S. Merry Christmas to all.................

Ozz would be the man to answer this question. He has mucho experience and is a HVAC journeyman.

[DQDick]

I buy that type of foam material from my HVAC man that sevices our store. Any heating and air place should be able to sell you some. The manufacturer of the furnace has been pretty specific at Rally's in the past that they don't recommend anything that restricts air flow to and from the furnace. Just make sure you have adequate air flow from whatever you end up with.

[kdeiss]

My thoughts are you are going to restrict air Flow we will get Ozz's opinion

[Ozz]

Good thing you caught me sober... I would not put in foam, your initial idea has merit, cut down a PLEATED filter and use that, I cut a couple of small L-shaped brackets 1"x1" or so to hold it in place and with the increased surface area of the pleated area, you won't be restricting the airflow much. Use a cheap pleat, not the expensive 3-M ones.
I tell my customers that the 3-M pleats are too restrictive for A/C use, as most homes have marginal airflow issues if they are split level, or 2 story, but the cheap pleats are Ok, winter time, you could use the 3-M, but I change the heat tap on the motor from the Red wire:low speed to the medium speed, sometimes Blue wire. Good question.
Merry Christmas to you Larry.

[mhs4771]

Unless there is an actual Air Return Duct on the stair return are you really gaining anything with all the other openings to the basement, underbelly, and anywhere else. Now on a former TT we had, the return grate was attached to the furnace directly below the fridge, so something there would have worked, but seems most 5ers the furnace is mounted behind the basement wall with the return just being open to that entire area.
Now this all could vary, depending on Floor Plan and exact location of the furnace.

[bigskyjimmy]

I was thinking the same way as Michelle and Ann ,I have put filters in the stairs for years and never had a problem ,there is so much air for the furnace to grab in the basement I never figured out why they even put slots in the stairs but then again I am not an expert

quote:Originally posted by mhs4771

Unless there is an actual Air Return Duct on the stair return are you really gaining anything with all the other openings to the basement, underbelly, and anywhere else. Now on a former TT we had, the return grate was attached to the furnace directly below the fridge, so something there would have worked, but seems most 5ers the furnace is mounted behind the basement wall with the return just being open to that entire area.
Now this all could vary, depending on Floor Plan and exact location of the furnace.

[Ozz]

Look at it this way, your furnace outlet vents supply the warm air to the unit, it circulates inside where we live and move around, where the cats, dogs, Ferrets and assorted carbon-based units move around. The air then goes under the steps (in my unit) into the basement area and back to the return air part of the furnace. The basement area is just a space that air goes thru to the return furnace, like a big duct.
The filter.. filters all the dust you kick up, all the Dog, cat and Ferret hair, dander and dirt that follows you in and circulates around the space the door when it opens.
I want as much of that air filtered as possible when it exits the floor registers into my sensitive nose and down my windpipe to my pristine lungs
If a fella does not care about that, then don't filter the air.

[bigskyjimmy]

And there you have it an explanation from an expert the Great and Powerfull Ozz now I get it

quote:Originally posted by Ozz

Look at it this way, your furnace outlet vents supply the warm air to the unit, it circulates inside where we live and move around, where the cats, dogs, Ferrets and assorted carbon-based units move around. The air then goes under the steps (in my unit) into the basement area and back to the return air part of the furnace. The basement area is just a space that air goes thru to the return furnace, like a big duct.
The filter.. filters all the dust you kick up, all the Dog, cat and Ferret hair, dander and dirt that follows you in and circulates around the space the door when it opens.
I want as much of that air filtered as possible when it exits the floor registers into my sensitive nose and down my windpipe to my pristine lungs
If a fella does not care about that, then don't filter the air.

[dieselguy]

On 3150RL's remember the big grill rig under the fridge. Look into it and you can see the furnace plain as day ... filters under the steps will do little until you address this grill opening as well.

[Ozz]

I agree, there are different configurations, you may need to place the filter elsewhere, and it may be the case where you can see the furnace, but the return air section is not there, I just don't know, BUT the return air has to have a route, and in my opinion, it should be filtered