AC Tonnage (Room BTU) Calculator by Avenir Developments

AC TONNAGE (ROOM BTU) CALCULATOR

Estimate the cooling capacity (BTU/hr & tons) your room needs using area/height, windows & sun, people & appliances, and local climate (Pakistan presets included). Add efficiency to see power draw and monthly cost. Use for planning—confirm with detailed HVAC design.

Units & Location

Units Switches input labels only. Metric (m, m²) Imperial (ft, ft²)

Climate Preset Sets base BTU/ft² by weather. Lahore (hot summers) Karachi (hot & humid) Islamabad (warm temperate) Peshawar (hot summer) Quetta (dry, cooler) Temperate (global) Hot & Humid (global)

Room Input Method Use size (L×W×H) or Area + Height.

Length × Width × Height Area + Height

Insulation / Build Quality Walls/roof/air-sealing quality. Excellent (insulated) Good (modern) Average Poor (leaky/light)

Room Size

Length Long side of the room.

m

Width Short side of the room.

m

Ceiling Height Taller rooms need more BTU.

m

  

Area auto-computed from L×W.

Area Floor area of the room.

m²

Ceiling Height Clear height value.

m

  

Use if you know area.

  

Windows & Sun

Window Area Total vision glazing area.

m²

Sun Exposure South/West = higher gains. Low (north / shaded) Medium (mixed) High (south/west) Very High (direct sun)

Glass / Frame Type Affects solar heat through glass. Single (aluminum/wood) Double glazed Low-E double Triple

Shading Curtains/film/overhangs. None / light Curtains / film Blinds / overhang Deep shade

People & Appliances

People in Room Avg. occupants during use.

Appliance Load (Watts) TV/PCs/lights—sum total.

Air Tightness Leakiness / infiltration factor. Sealed (good) Average Leaky

  

Efficiency & Cost (optional)

AC Efficiency (EER) BTU/hr per Watt (typ. 9–12).

Daily Run (hours) Avg. hours/day in season.

Electricity Tariff Per kWh (PKR or local).

/kWh