How do I size an air conditioner for my home?

A proper Manual J load calculation uses your home's insulation, window type and orientation, air-sealing, shading, and internal heat loads to compute the actual BTU/hour the house needs.

Rule-of-thumb sizing (1 ton per 500-600 sqft) almost always oversizes — and an oversized AC short-cycles, which cools the air without pulling humidity out (resulting in a clammy 72°F house) and wears out the compressor years sooner.

Utah's dry air makes oversizing less uncomfortable than in humid states, but the short-cycle wear is the same. Right-sized equipment also tends to be quieter and uses less electricity. We run Manual J on every replacement quote, not just as a selling point but because ACCA and most manufacturer warranties require it.