Use this online HVAC load calculator to estimate room cooling load in BTU/h, refrigeration tons, and kW from room size, occupancy, windows, equipment load, insulation, and climate.
This is a simplified cooling estimate for planning. Detailed HVAC design should also consider orientation, infiltration, glazing type, latent load, and ventilation requirements.
An HVAC load calculator estimates how much cooling capacity a room needs. It starts with room area, then adjusts for occupants, windows, internal equipment heat, insulation quality, and climate. The result helps you estimate the required cooling capacity before selecting an air conditioner or HVAC unit.
This cooling load calculator is helpful for bedrooms, offices, classrooms, shops, and other indoor spaces where you need a quick estimate of AC size. It is especially useful when comparing whether a room may need a 1 ton, 1.5 ton, 2 ton, or larger air conditioning unit.
A quick HVAC load estimate like this can make early equipment selection easier and helps narrow down realistic cooling capacity before a full mechanical design review.
| Variable | Meaning | Typical Unit |
|---|---|---|
| L, W | Room length and width | m |
| A | Floor area | m2 |
| Qbase | Base cooling load from room size | BTU/h |
| Qtotal | Total cooling load estimate | BTU/h |
| Tons | Cooling capacity in refrigeration tons | TR |
Enter room dimensions in meters, equipment load in watts, and people and windows as whole-number counts. Results are shown in BTU/h, kW cooling, and refrigeration tons.
These are standard HVAC sizing units used in residential and commercial air conditioning selection.
Room = 5 m x 4 m, 2 occupants, 2 windows, 300 W equipment, average insulation, moderate climate.
Area = 20 m2
Base load = 20 x 500 = 10000 BTU/h
Occupants extra = 600 BTU/h, windows = 1000 BTU/h, equipment = 1024 BTU/h
Total load = about 12624 BTU/h, which is about 1.05 tons.
Room = 8 m x 6 m, 6 occupants, 4 windows, 1200 W equipment, average insulation, hot climate.
Area = 48 m2
Base load = 48 x 500 x 1.15 = 27600 BTU/h
Occupants extra = 3000 BTU/h, windows = 2000 BTU/h, equipment = 4094 BTU/h
Total load = about 36694 BTU/h, or roughly 3.06 tons.
Cooling load is influenced by more than floor area alone. Solar heat gain through windows, building orientation, ventilation rate, ceiling height, occupancy pattern, computers, lighting, and insulation quality can all change the final air-conditioning requirement. This HVAC load calculator gives a useful planning estimate for room cooling capacity, but detailed HVAC design should still be checked whenever comfort, ventilation, or equipment performance is especially important.