Work out air conditioner tonnage instantly with clear inputs, formula shown and shareable results.
Cooling load starts from room volume at roughly 45 W per cubic metre, adjusted for solar gain and adding about 120 W per occupant. One ton of refrigeration is 12,000 BTU/h or 3.517 kW, so a typical 22 square metre room needs a little over one ton.
Cooling load
load = volume x 45 W/m3 x sun factor + occupants x 120 W; tons = BTU/h / 12000
Yes. An oversized unit short-cycles, cooling the air quickly without removing humidity, leaving the room cold and clammy while wasting energy.
It is the cooling rate needed to melt one short ton of ice in 24 hours — a legacy of ice-based refrigeration.