Heating Ventilating and Air Conditioning

What size heat pump system is needed for an 1100 square foot home?

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Wiki User
02/17/2007

I just did extensive research before having a new heat pump put on my house. consumer reports and various books at the library said square footage is not the best or the most acccurate way to figure sizing the unit. there is a manual J that a.c.companys should use and also computer software one can purchase online to size it yourself. everything i read stressed that most a/c companys install units larger than needed and indeed all the companys that gave me estimates simply asked my square footage and took my word about it and then told me the tonnage i needed based on my numbers and eyeballing the existing unit. they all came up with a minimum size of 4 and up to a five ton unit! my research told me that the max size i really needed was 2.5 to 3 tons. long story short my house is 1200 sq ft minimum and i bought a 3 ton unit with a seer rating of 13[ the higher the seer rating the more efficient, but with the higher rating is more complicated repairs more often according to consumer reports]. my old unit was plenty big enough for my house and when they put the 3 ton on it dwarfed my old unit. point being that even at 3 tons i probably bought bigger than needed. back to your question. buy no bigger than 3 ton and a 2 1/2 ton will probably do. get one with a seer factor of 13 no more no less. buy a good brand such as my lennox and lastly dont let them bullcrap you into anything bigger or extended warrantys. get the longest warrantees and estimates from at least 4 to 5 companys.and then make them give you their best price and dont be afraid to play one against another. my original estimate started at almost 7 grand and the one i chose was 5 grand even and came with with a programmable thermostat. dont pay more than 5 grand & shoot for less. dont budge when they try to steer you and they will try!!! let me know how you come out!