Hi Folks,

First time poster here. I recently moved into a brand new 2-storey home in the suburbs of Toronto. The home is 4300sqft (not including basement). The basement is unfinished. We have 10ft ceilings on the main floor, 9ft on the 2nd floor. We also have a Vanee 60H HRV.

I have the following Carrier Comfort Series furnace installed in the house -- 59sc5a100s21-14. Based on my research, this is a 100k BTU furnace that has a 1400cfm blower (max cooling is 1545 cfm according to the manual).

http://www.docs.hvacpartners.com/idc...9sc5a-05pd.pdf

My builder did a heat load calculation as part of the building permit. That calculation calls for a 3.56 ton AC. I have heard very mixed reviews from HVAC contractors here, ranging from 3.5T to 5T. It is clear that I cannot go ahead with a 5T (oversized, blower too weak), but I need some advice on where to end up between 3.5T and 4T. From my reading on this forum, it appears that 350cfm/ton is acceptable for Carrier. That would lead me to believe that I should be good with 4T, however some HVAC contractors have indicated I need AT LEAST 400cfm/ton to avoid freezing of the coil.

I am planning on purchasing the Carrier Infinity 24ANB6 AC.

I would greatly appreciate any expert advice on how to approach this. As I've said, I've heard mixed opinions from the HVAC contractors I've contacted thus far.

Thanks in advance!