BTU Sizing Calculator: What Size AC Does Your Home Need?

BTU

Room BTU Sizing Calculator (San Antonio)

Room length (ft)

Room width (ft)

Ceiling height (ft)

Base rule assumes 8 ft.

Sun exposure

Insulation quality

Regular occupants

+600 BTU per person after two.

Heat-generating appliances

ZIP/Area (optional)

Rule of thumb ≈ 20 BTU/ft², then adjust.

HOME

Home size (ft²)

Use conditioned area.

Stories

Avg ceiling height (ft)

Cooling climate

Insulation & sealing

Window exposure

Regular occupants

Duct location

Kitchen use

Heating climate

ZIP/Area (optional)

Baseline ≈ 22–24 BTU/ft² in hot/humid SA.

Air Conditioning tips & efficiency

Heating & Cooling overview & resources