Running A/C vents from attic to basement.


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Old 02-22-11, 05:56 AM
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Running A/C vents from attic to basement.

http://i1218.photobucket.com/albums/...asement3-3.jpg

This is a plan for finishing the basement. It's a one story ranch and air handler is in attic with ducts running to center of each room ceiling.

I am considering running A/C ducts from existing "main duct" in attic through closet in the middle of first floor. Then vent one in each room?

Would probably like to run a radon tube up through the closet to exhaust on roof... mainly to vent soil gasses. Do I have to caulk the perimeter before studding the walls?

Does this sound right? Will these changes cause problems with boiler combustion?

Also, I figured I would tap into boiler runs with some pex through walls and either baseboard or radiators? Would be nice to have a separate thermostat in basement and that would require some kind of solenoid zoning controls, right?
 
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Old 02-22-11, 02:32 PM
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Originally Posted by Mr Obvious View Post
http://i1218.photobucket.com/albums/...asement3-3.jpg

This is a plan for finishing the basement. It's a one story ranch and air handler is in attic with ducts running to center of each room ceiling.

I am considering running A/C ducts from existing "main duct" in attic through closet in the middle of first floor. Then vent one in each room?

Would probably like to run a radon tube up through the closet to exhaust on roof... mainly to vent soil gasses. Do I have to caulk the perimeter before studding the walls?

Does this sound right? Will these changes cause problems with boiler combustion?

Also, I figured I would tap into boiler runs with some pex through walls and either baseboard or radiators? Would be nice to have a separate thermostat in basement and that would require some kind of solenoid zoning controls, right?
Your air con. works better coming out of the ceiling, why would you want to change it. I think that what you are saying, that you are going to put air down low?
If you want your boiler heat to be zoned out for basement and main floor, then you would have to install two zone valves or two pump to control the two zones, plus the re piping. Paul
 
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Old 02-22-11, 04:39 PM
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Originally Posted by paul52446m View Post
Your air con. works better coming out of the ceiling, why would you want to change it. I think that what you are saying, that you are going to put air down low?
If you want your boiler heat to be zoned out for basement and main floor, then you would have to install two zone valves or two pump to control the two zones, plus the re piping. Paul
To be more clear, I don't want to change existing ducts on main/1st floor but run new ducts FROM existing in attic through closet at center of main/1st floor to basement ceiling. Hope this clears up my plans. Currently our basement is unfinished and I'm trying to plan the HVAC before I get into the framing.
 
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Old 02-22-11, 05:20 PM
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Originally Posted by paul52446m View Post
Your air con. works better coming out of the ceiling, why would you want to change it. I think that what you are saying, that you are going to put air down low?
If you want your boiler heat to be zoned out for basement and main floor, then you would have to install two zone valves or two pump to control the two
zones, plus the re piping. Paul


The boiler currently has 2 zones - bedrooms and everything else. Each zone has what seems to be a mechanically controlled valve, but only one pump. I guess there would be no heat control. The valve is either open or close. UNLESS what if valve is partially closed or would this merely slow the time it takes to reach temperature really having no affect on final temp? So separate pumps and separate solenoids for each zone would achieve individualized or zone heating. Do you think a boiler currently sized for 900 sf can handle the extra 900 sf of finished basement? The boiler is 105000 btu.
 
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Old 02-22-11, 06:51 PM
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Your unit should be sized for just the main level! Adding the basement will under size your unit! I'd look into adding a unit just for the basement
 
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Old 02-22-11, 11:12 PM
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Originally Posted by airman.1994 View Post
Your unit should be sized for just the main level! Adding the basement will under size your unit! I'd look into adding a unit just for the basement
What's the next less expensive thing to do, maybe a wall mounted gas burner, wth venting? And electric heater for bath (which will probably never get used - we could just rough in wiring should the need arise.
 
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Old 02-23-11, 12:22 PM
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Originally Posted by Mr Obvious View Post
What's the next less expensive thing to do, maybe a wall mounted gas burner, wth venting? And electric heater for bath (which will probably never get used - we could just rough in wiring should the need arise.
You really need to have a heat loss done for both heating and cooling.
If you don't you might spend a lot of money the wrong way. Your basement does not need as much heat or cooling as the main floor.
Look at your boiler , it has a input, out put, and a IBR output.
What is your IBR output and how much what footage of radiation do you have in the house? Do you have anything else tied to this boiler, like for hot water? The valves you are talking about were probable installed to use them for balance the heat, so you might need 3 zone valves and stats. I would bet once you do the heat loss that you boiler would be large enough. Paul
 
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Old 02-23-11, 07:11 PM
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Originally Posted by paul52446m View Post
You really need to have a heat loss done for both heating and cooling.
If you don't you might spend a lot of money the wrong way. Your basement does not need as much heat or cooling as the main floor.
Look at your boiler , it has a input, out put, and a IBR output.
What is your IBR output and how much what footage of radiation do you have in the house? Do you have anything else tied to this boiler, like for hot water? The valves you are talking about were probable installed to use them for balance the heat, so you might need 3 zone valves and stats. I would bet once you do the heat loss that you boiler would be large enough. Paul
The furnace is a PWB-4d Dunkirk water boiler. Our water heater is separate.
Furnace has 105 input MBH, 74 I=B=R rating MBH. Plumber is coming tomorrow. Will ask about heat loss for heating and cooling.
 
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Old 02-23-11, 08:47 PM
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Originally Posted by Mr Obvious View Post
The furnace is a PWB-4d Dunkirk water boiler. Our water heater is separate.
Furnace has 105 input MBH, 74 I=B=R rating MBH. Plumber is coming tomorrow. Will ask about heat loss for heating and cooling.
You did not tell me the footage of radiation in the main floor.
If you had full size radiation with a one gal. per min. flow, 180 degree temp you would get about 600 Btu per foot of radiation. so if your IBR
out put is 740000 divided by 600 is 123 foot of radiation. This means
your boiler can handle 123' of radiation. I don't know where your live,
and how well your home is insulated and how many window and how good these windows are. When you redo your basement, put good insulation on walls and good windows. It should take less heat to heat your basement than your main floor, as long as you insulate in good. Tell me how much radiation you have in the main floor.
Also keep in mind that the difference between the output and the IBR output is the heat you lose from the piping system, but since you don't have the pipes in a craw hole you are losing this heat to the house. Paul
 
 

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