Recapture Cooler Basement Air? (AC Question)

When the AC is being used, my basement tends to get about 5 degrees cooler than the first floor. The basement is used for laundry, storage and my workshop, so it doesn't need to be that cold.
Here's my idea: Cut a hole in my return trunk, near the floor, to recapture the cooler air and send it back upstairs. I'd install a filter and design it so it could be easily sealed up in the winter.
So, if this isn't a ridiculously bad idea, how would I go about determining the correct size for the opening?
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Seems to me that it would make more sense to insulate all of your ductwork leading to the upstairs so that you're not wasting any of that cool air on the basement.
Tom G.
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On Mon, 18 Jun 2007 07:35:09 -0700, DerbyDad03 wrote:

Sorry to inform you, yes it is a rediculously bad idea :)
Getting air out of a room is just as important as getting it in when you want to control the temperature. If you cut the return, you will stop air from leaving the rooms upstairs. That will mean less air will enter those rooms. Perhaps that air is cooler now, but I am willing to bet the reduced quantity is going to hurt you big time.
I doubt your A/C has problem cooling the warmer air it sucks in from the returns now. If it does you need some work.
I closed all my basement vents.
what you can do is run the fan only. the air coming out will still tend to be cooler. but it raises the household humidity.
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Thanks for the response.
All of my basement vents are closed and I've sealed all the seams on the furnace/blower unit. I haven't attempted to seal all of the duct work and insulating all of it would be a major undertaking. I'm not sure I could do either without dismantling the whole system. A lot of the ductwork is right up against the floorboards/joists, so there is not a lot of room for insulation or even room to wrap the seams with tape.
I have an "chute" where the main stack runs from the basement to the attic, with an plumbing access panel on the second floor landing. What if I dropped a length of 4" PVC down this chute and rigged up a fan to draw the air up from the basement to the second floor? It would drift back down to the first floor via the stairs.
One last question about something you said:
-- I doubt your A/C has problem cooling the warmer air it sucks in from the -- returns now. If it does you need some work.
How would I know? This is my first full season with AC and I really don't know how to tell if it's working correctly. It seems to take a very long time to cool the house down, especially compared to how fast the same system warms the house in the winter.
Anything I can check? Return air temp vs. output air temp?
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On Mon, 18 Jun 2007 09:28:30 -0700, DerbyDad03 wrote:

If you can eventually get a 15 degree difference between inside and outside during the hottest part of the day, you AC is working well. Most of the time 10-12 degrees is fine because in addition to cooling your system is removing humidity from the air which is a big part also on how you feel inside.
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I open the door that contains the furnace filter this grabs the cool air from downstairs and pushes it upstairs, most days we don't even need to run the air just the furnace blower.

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-- I open the door that contains the furnace filter this grabs the cool air -- from downstairs and pushes it upstairs, most days we don't even need to run -- the air just the furnace blower.
Thanks, but there is no door on this unit. I know what you mean though...my old furnace had a door on the compartment that housed the blower and filter.
On my new unit, the filter just slips into a slot in the ductwork just before the blower. If any basement air is going to be sucked into the system via the filter opening, it's already happening.
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On Mon, 18 Jun 2007 12:06:07 -0700, DerbyDad03 wrote:

Do you have a humidifier on this furnace?
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No, I do not. Why do you ask?
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On Tue, 19 Jun 2007 05:55:24 -0700, DerbyDad03 wrote:

You could have opened the door and let the air in there.
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DerbyDad03 writes:

Bad idea. You're confusing temperature with heat.
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Thanks for the detailed explanation. You've cleared it up completely.
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wrote:

I like the idea.
Just provide both a supply and return to the basement and your other rooms should be cooler. By supply, I mean to allow the supply to the nearest room to enter the basement before being sucked back to the evaporator.
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-- -- Just provide both a supply and return to the basement and your other -- rooms should be cooler. By supply, I mean to allow the supply to the -- nearest room to enter the basement before being sucked back to the -- evaporator.
This is an interesting response. Now that you mentioned this, I realized that there is no cold air return in the basement other than whatever gets sucked in via any openings the ductwork and the slot around the filter. I haven't used a smoke puffer to check for leaks in the system, but I assume there are many.
I have closed the 2 outlets in the basement, but now I'm wondering if I should open them *and* cut a return opening in the return trunk. Wouldn't this make the basement just like any other room that has a supply and a return? Would this help to balance the system?
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