I am purchasing a new A/C system for a 28yr old, 1768 sq ft, 2 story house in the CA coast. The bidding contractors have so far given proposals for 3 ton and 4 ton A/C, and one told me that I should just go for a 10SEER A/C because my ductwork is too narrow and was built for my old heating system only. I originally wanted a 13 SEER A/C.
Should I go with his proposal for a 4 ton, 10 SEER system or should I go for a 13SEER one?
COMMUNITY FORUM
Based on only the Sq. footage of the home, I can only guess at the tonage needed, but excluding any major cathedral ceiling space, sun exposure,....4 ton is right @ a 2000 estimated sq.ft. house.
4 ton is 4 ton. I don't care if you have a 10 seer or a 12 seer. Each ton of cooling,(12,000 btu/hr) requires 400cfm, air flow [cubic feet/minute] to utilize it's given value. 4x12= 48,000btu/hr : This 4 ton unit requires 1600 cfm. delivery from your blower. If the duct is too small, wether it's 10 or 12 seer you have problems.....
Since your duct work is in Q:? you need a trunk line of 20"x12" to accomendate 1600 cfm.......this is if the furnace is at one end of the house. split the diff. if in the middle with a "T" commong off the top.
It's hard to give you solid answers, but good luck.
10/12/13 SEER refers to the amount of electricity (vs) work peformed each unit can perform. Higher, the better....But get ready to spend the "Bucks". The national average of life expectancy of a given a/c unit is 12 to 16 year's. The diff between 10 and 1 2seer is about $1,000.00 give or take.....
Go with 10 seer.
4 ton is 4 ton. I don't care if you have a 10 seer or a 12 seer. Each ton of cooling,(12,000 btu/hr) requires 400cfm, air flow [cubic feet/minute] to utilize it's given value. 4x12= 48,000btu/hr : This 4 ton unit requires 1600 cfm. delivery from your blower. If the duct is too small, wether it's 10 or 12 seer you have problems.....
Since your duct work is in Q:? you need a trunk line of 20"x12" to accomendate 1600 cfm.......this is if the furnace is at one end of the house. split the diff. if in the middle with a "T" commong off the top.
It's hard to give you solid answers, but good luck.
10/12/13 SEER refers to the amount of electricity (vs) work peformed each unit can perform. Higher, the better....But get ready to spend the "Bucks". The national average of life expectancy of a given a/c unit is 12 to 16 year's. The diff between 10 and 1 2seer is about $1,000.00 give or take.....
Go with 10 seer.
Write back if you need help. 
My mind can think alot faster that I can type...........m2112@adelphia.net
[This message has been edited by HOLLYWOOD (edited March 17, 2000).]
