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Old 05-23-2007, 06:15 PM  
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Default Old House, New A/C, one thermostat, upstair too hot--PLZ help!

Hello All!
My house is 40+ years old, actually its probably closer to 50 years old. My family has been living here for 25+ years. Now originally the house did not come with central air conditioning and was installed about 20 years ago. Last year we had to replace, pretty much the whole unit(the outside compressor and in the inside of the house the heat exchange, and such, sorry I do not know much about the technicalities of it all). Anyways, we do not have more then one thermostat or compressor and the thermostat is downstairs. The downstair's temp is great---always great, I have absolutely no complaint here. However, go upstairs and there is a noticible difference in how much hotter it is. Upstairs, the cool air comes out alot less powerful and Im guessing once the thermostat reads 75 downstairs the A/C shuts off regardless of the temp upstairs. I was wondering besides having to buy a whole new unit for the upstairs is there a way in wich I can increase the air flow upstairs or any other recomendation for cooling the upstairs would be great.

also, we put new insiliation in our attack.

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Old 05-24-2007, 10:48 PM  
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Welcome AJS807:
A couple of things you can try are:
1. Turn the thermostat fan position to ON. This will continue to mix the air in the house and help to balance the temperature.
2. It is possible to partially block some of the ducts on the ground floor, forcing more air to the second floor.
3. If you are opposed to running the fan on the unit all the time, you could put a ceiling fan at the top of the stairs blowing down, which would give you some mix of air.
4. One more thing, Is any part of your duct system made of round flex-duct? If so, the wire reinforcing in the flex-duct defeats the flow of air. It should be changed to smooth metal pipe with sleeve insulation on the outside.
Please post back and let us know how it goes or for further questions.
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Old 05-25-2007, 06:16 AM  
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Join Date: Apr 2006
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as warm air has a tendency to "rise", this is one of the reasons for a warmer second floor.
RETURN air is needed in this second floor area in order to "draw" this warm air back to the unit. And it's always best to have return air inlets placed in the highwall,or ceiling area for cooling.

glennjanie suggested partially blocking off some of the lower floor ducts on the ground floor . Unless you know exactly what you are doing this is a bad idea, as blocking off too much can create other costly problems.
"Partially " is very hard to define, unless you have some know-how and air measuring instruments.
Also, is there a door opening to this upper area that can be kept closed and stop the ground floor warm air from rising to the upper level?
The main key to eliminating your problem though is to have RETURN air in this upper level.
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