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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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Duct calcuction

Customer Question

duct calcuction
Submitted: 1 year ago.
Category: HVAC
Expert:  Rick replied 1 year ago.

What is your question?

Customer: replied 1 year ago.
ac duct ???? my daughter room 12.6 x 13.1 8ft ceiling .981 cfm room hot 1- 6" drop
my son room 13.3 x 13.6 8ft ceiling 1 - 6" drop room hot
Customer: replied 1 year ago.
had ac duct changed 8 room all 6" drops
Expert:  Rick replied 1 year ago.

Are you asking what the proper size of the duct should be for those rooms? if so I need the load for each room. Square footage isn't an accurate way to size anything. I sorry but your .981 cfm per room can't possibly be right.

Customer: replied 1 year ago.
3ton unit
nikki room 12.6 x 13.1 = 162
andy 13.3 x 13.6 = 178
bathroom 13.6 x4 = 53
living room 21 x 13.75= 284
master bedroom 13.6x14.25=190
dining room 14.3x 10.4=146
400cfm + 3ton = 1200cfm
each room total 1223
all room have 6"drops
living has 2
kitchen / dining has 3nikki and Andrew are hot
Customer: replied 1 year ago.
add little bathroom 14.3x10.4=56 in 1223 figure
Expert:  Rick replied 1 year ago.


162 = 7"

178 = 8"

I assume those are the rooms you mention as too hot.

Customer: replied 1 year ago.
cant call at work changed nikki room to 7 duct from the unit changed andy room to 8" how about bathroom changed to smaller size
Expert:  Rick replied 1 year ago.

Bath room is bigger (5") than needed but you'll appreciate the extra heat in the winter. I wouldn't bother changing it.

Expert:  Rick replied 1 year ago.

Do you have any more questions?