Hi,

I had my basement finished a few years ago. There were 2 registers in the basement
That existed along the main line and they are utilized. One register is in a room where the
Utilities are [gas water heater and furnance] and the other is in the main living area.
I have installed grills in a couple places between the rooms as requested by the County
People so that combustion air is supplied. There are 2 smaller rooms in this basement that
Have no registers.

Anyway, I was thinking it would be a good idea to install a return somewhere. I have read
That its best for the return to be near the floor instead of high on a wall. My questions are:

1. Generally speaking, what size should this return be? My house is a 2 story colonial, not
Huge, but decent size. Remember I only have those 2 registers in the basement.

2. I get a bit of humidity in the basement in the summertime. I generally close the
Registers in the basement, because it is always cool down there. Is it OK for a return to
Pull cool air from the basement when the registers are closed?

Any other advice about the best configration of this would be appreciated. My main
Objective was to get some of humidity out of the basement via some air flow. I
Already have a dehumidifier down there.

Thanks,
Mike

If you pull the humidity from the basement with your furnace blower that also means that the A/C unit will have to remove the humidity if you have A/C. I do not suggest you pull humidity from the basement into the first or second floor of your house unless you have a A/C unit that will remove the moisture first.

Quote:

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Originally Posted by hvac1000

I do not suggest you pull humidity from the basement into the first or second floor of your house unless you have a A/C unit that will remove the moisture first.

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Don't all Central Air units remove humidity from the air-flow? I assumed that as the
Air passes over the coils, that the moisture drops to the pan and is discharged. Isn't
That why water comes out of that pvc pipe connected to the pan? Unless you are
Talking about me leaving the fan on all the time to circulate air [I wasn't planning on
Doing that]. My main concern was that drawing air from the basement with the
Basement registers closed would draw air from under the slab [radon problem?] or
Sump pumps, or it will try to pull combustion gases from the gas appliances. Though
All my gas appliances have powered fans that send the exhaust outside.

Mike

You never mentioned you had A/C in your first post?
Your A/C might be working at maximum capacity already. It may not be able to remove all the moisture from the basement air.
Yes you could have a problem with combustion air if ventilation air is pulled from the furnace area.

Do what you want but I try never to use basement air for circulation in the rest of the house.

Quote:

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Do what you want but I try never to use basement air for circulation in the rest of the house.

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So then in the summer when I close the registers, the basement essentially becomes
Dead air space, and in the winter when I open the registers, it tries to push air into
The upper floor (i.e. up the stairs and under the door assuming a gap).

I know I can do what I want, just looking for some advice from people who know more
About it than I do. I assumed that when a basement was finished most people
Install a return, but I wasn't sure. I suppose I was thinking that its not good to have a
Dead air space which may contain humidity, like in a basement.

Thanks,
Mike

I gave you good advice. You did not want to listen to common sense. Just because you get a answer you do not like does not mean that good advice was not given. Good luck with your project.

Quote:

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Originally Posted by hvac1000

I gave you good advice. You did not want to listen to common sense. Just because you get a answer you do not like does not mean that good advice was not given. Good luck with your project.

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You know, I just wanted some additional information and possibly some other
Opinions. I never said I didn't like your advice. But you seem to have a problem
When someone asks for additional information. You need to relax dude. If you
Don't enjoy the conversation, then don't respond.