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Building a house: What air conditioning system goes in?

How do you calculate air conditioning tonage for a 2 story house? For example, how do I know if I need 3 tons for the top floor and 4 tons for the bottom floor? How do I determine this? The bottom floor is 1500 sq ft and the top is 1500 sq st.

Public Comments

1. Well you wont be able to install it yourself I don't think, so when you call the heat and ventilation people they will tell you what you need for your square footage.
2. Well, if you can do a Manual J load calculation you have it whipped! This determines the heat gain your particular home is subject to and leads to a determination of the cooling capacity tonnage you need. This is something a HVAC contractor can do for you. If you want to know a bit more about choosing systems, try this article: http://www.thisoldhouse.com/toh/article/0,,194722,00.html?xid=yahoo-answers&partner=yes And if you decide to turn the sizing over to an HVAC contractor, here's how to choose a good one (Tip: if he/she doesn't do load calcs to size your system, choose somebody else): http://www.thisoldhouse.com/toh/article/0,,218945,00.html?xid=yahoo-answers&partner=yes