what size central ac unit would I need for my house. Its1450 sq.ft.?

If you go to http://www.alpinehomeair.com/ web site they have a very helpful program that helps you find what you need.

ok it depends on where you live

for example lets do Bev.hills CA

since only the upstairs requires cooling and the basement doesnt require cooling ( or nearly as much as upstairs) you size it for the sq footage above ground

further south you are size it at 450 sq ft per tonne north like seatle size it at 550 sq ft this is the rough guide

there is a formula to use which your a/c guy will size out the house for you but in CA you would require a 1.5 tonne min but allow extra half tonne so it doesnt work at its maximum. since you have a walkout basement you would have to size half of the basement so you would require a 2 tonne and again allow half a tonne

2.5 tonne should be sufficient

depending on your furnace you can slightly increase your A frame by about half a tonne

one ton of ac will cool approximately 450 sq feet [300 if lots of windows or poor insulation ]and your cooling part of your basement which is already cool .taking that in to consideration i would suggest 2and one half to 3 tons of cooling max

you will be able to desire to. i does no longer propose it although. Like mentioned in the past, sq. photos, domicile windows, doors, even the homes area will confirm how huge or small the device could be. ultimate guess is to call an authorized HVAC salesclerk to do the load calculation and duct paintings assessment, then bypass from there.