Proper Duct Size

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  #1  
Old 05-16-00, 12:47 PM
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How do I determine the proper duct size. I had a new AC/Furnace installed, it is much,much larger than old one. Some rooms are freezing and baking while others are oposite. Thanks for any help
 
  #2  
Old 05-18-00, 09:03 PM
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a general rule of thumb is 2 x the number of runs + 2 by 8 will size the duct for a house in other word 10 runs x 2 + 2 = 22by 8 duct
However it sounds like you need to balnce your house. Do you have dampers in each run? If not install them and turn down the ones that are getting to much air forcing more air in the ones that are not be patient this may take a few tries to adjust correctly
There may be other problems such as;
Do you have enough return air?
Is the thermostat located correctly?

More often than not we have found that it is not the duct size that causes the problem
Good Luck I'll check back to see how you are doing
Louie
 
  #3  
Old 05-19-00, 08:12 AM
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Thanks Louie:
I believe the theromstat is located correctly (close to the return). Will do acheck on the return air. You have given me the starting place and I appreciate it ver much. I wish you well, Deltadude
 
  #4  
Old 05-19-00, 05:14 PM
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I would like to know something???? Why would you want the thermostat near the return? I aways install mine, on an inside wall, away from both supply and return, 5' up on the wall and at least 3' from a corner..I'ld like some feed back on this..
 
  #5  
Old 05-31-00, 08:05 PM
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We try yo put the t-stat near a return on a residential application for two reasons
first we like to put a double return air in a hallway or other centeral location second, the stat will then not only get a good overall reading of the house temp but be in a good general location for operation
I am open to other ideas if anyone has one
Thanks
 
  #6  
Old 06-01-00, 11:45 PM
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why is your AC/furnace much much bigger then the old? It sounds like you were way undersized before or way oversized now.Did they actually figure the heat gain/heat loss for your home? Just curious. Best regards...Bela
 
  #7  
Old 06-05-00, 08:07 AM
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Dear Bela:
I believe to old one was undesized and the new one is over size. The house is 4,500 SFT, with 12' celings.With all the help y,all give We will get it right. I truly appreciate all the help and advice. DD2yk
 
 

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