Many local HVAC companies just guess the size of the AC unit and therefore I decided to run my new house data through a Manual J compliant software. Depending on design summer temperature I obtain the following AC size (in tons) recommendations
Summer Temp Size 1 Size 2 90F 4.76 6.02 95F 5.04 6.46 100F 5.32 6.89 105F 5.61 7.33
The house is being build near Seattle where the max summer temp rarely exceeds 105F but gets to 100F for a week or so during summer. 90F can stay with us for few weeks per summer.
I am a bit confused about two sizing recommendations:
Size 1 is based on sensible and latent heat gain Size 2 is based on 75% Sensible Capacity
I do not want to oversize my A/C unit but I do not want to significantly undersize it either. What do you think? Thanks.