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# how many tons do i need

#1
07-20-08, 07:30 PM
Member
Join Date: Sep 2006
Posts: 17
how many tons do i need

hey all,
i have a 2000 sqft house how big of a unit do i need to cool my house efficiently?

thanks,
rodchar

#2
07-20-08, 07:59 PM
Member
Join Date: Dec 2007
Location: U.S.A.
Posts: 1,127
You should run a heating/cooling load calculation. Rules of thumb (which is what you seem to be interested in getting) could backfire since outdoor conditions are different depending on the geographical location of your house.

A factor that many contractors use (in my area) to get an "estimate" is 1CFM per foot-square (of living space). Another factor (for standard construction) assumes that an a.c. system would deliver 400CFM per Refrigeration Ton (a refrigeration ton equals 12,000Btuh)
For your house then, 2,000 ft2 would require 2,000CFM, which in turn would require a 2.5-ton unit. But I must warn you once more: THIS IS A "GUESSTIMATE". You should perform a full load calculation; that is the only safe way to get the job done right (select the right unit).

#3
07-21-08, 06:15 AM
Member
Join Date: Sep 2006
Posts: 17
Re:

Thanks for the insight,
rod.

#4
07-21-08, 07:22 AM
Member
Join Date: Dec 2007
Location: U.S.A.
Posts: 1,127
My math obviously was not at prime yesterday...

2,000CFM would be 5 tons, not 2.5 as I posted yesterday.
400CFM per ton x 5 tons = 2,000 CFM