We are in our first house and need to replace the existing a/c unit (a 20 yr old 2.5 ton Lennox, original from the build). Our home is located in Ottawa, Ontario, Canada, is 1700 square feet, all new windows, a fair amount of shade, and we have rather humid summers. Attic is R30, walls are siding with brick in the front and R19.
We've had 4 guys in for quotes and they are equally split on whether we need a 2 ton or a 2.5 ton unit.
Both Lennox (XC14) guys said 2.5 tons, and went only by eyeballing the square footage and that is house is 2 storeys.
The Bryant (116B) and Trane (XR15) guys said 2 tons would be sufficient since we don't have a ton of windows and only get sun on one side of the house (west), which is half shaded by trees.
We're afraid if we go with the 2.5 ton it might be oversized and not dehumidify properly. What should we do?