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Discussion Starter · #1 ·
I am trying to install a furnace in my home, The furnace is a gibson 95% 70,000 btu. I live in Tenn near the MS state line so winter is not bad coldest it gets in the dead of winter is about 20 degrees and warms above freezing durning day. My home is small 24ft wide by 58 ft long. The blower cfm size is 1450 cfm without filter. I am trying to figure out the trunk size for ducting and should it be all one size or should it start out large and be reduced . I am talking about the main duct that goes the length of house which is being installed in attic furnce in closet. Also how many air returns should I have and the size of them. Any help would be great. Thank you for you time Charlie
 

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I am trying to install a furnace in my home, The furnace is a gibson 95% 70,000 btu. I live in Tenn near the MS state line so winter is not bad coldest it gets in the dead of winter is about 20 degrees and warms above freezing durning day. My home is small 24ft wide by 58 ft long. The blower cfm size is 1450 cfm without filter. I am trying to figure out the trunk size for ducting and should it be all one size or should it start out large and be reduced . I am talking about the main duct that goes the length of house which is being installed in attic furnce in closet. Also how many air returns should I have and the size of them. Any help would be great. Thank you for you time Charlie
I would like see an insulated 8"X12" main duct going two ways. If it has to go one way only you will need to start out with a 9"X 25" or a 12"X18" something with 200sq/in ID. Then reduce after 20' or so. This duct needs insulated either inside or rapped outside. Adjust the size up for inside insulation.
You don't say how many rooms, but you will need 4- 8" round R/A ducts and 8- 6" S/A ducts, all need to be insulated.
8" run = 50 sq/in and a 6" run = 30 sq/in.
I hope it helps
 

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Discussion Starter · #3 ·
I would like see an insulated 8"X12" main duct going two ways. If it has to go one way only you will need to start out with a 9"X 25" or a 12"X18" something with 200sq/in ID. Then reduce after 20' or so. This duct needs insulated either inside or rapped outside. Adjust the size up for inside insulation.
You don't say how many rooms, but you will need 4- 8" round R/A ducts and 8- 6" S/A ducts, all need to be insulated.
8" run = 50 sq/in and a 6" run = 30 sq/in.
I hope it helps
Thanks Charlie
 
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