Air conditioner tonnage calculator

One ton of cooling is 12,000 BTU/h, about 3.52 kW; the ton is a marketing size, so the estimate also shows the standard unit size it snaps up to. The chart underneath is the ENERGY STAR room table with published rule adjustments: 10 percent either way for sun, 600 BTU/h per person past two, 4,000 BTU/h for a kitchen, height over 8 ft scaling the load, 3.412 BTU/h per watt of appliances, and 15 percent extra for poor insulation. A real ducted or mini-split install needs a proper load calculation, so treat this as a starting point before you talk to an installer. Oversizing cools fast but short cycles, which leaves a clammy room and a shorter-lived compressor.