Commercial BTU Calculator
About Commercial BTU Calculator
A commercial space carries a heavier load than a residential room of the same floor area, and this calculator uses 32 BTU/h per square foot for cooling to reflect it. Three factors drive the difference. Occupant density is far higher, since an office or shop packs more people into the same area than a house does, and every person is a continuous heat source. Equipment density is higher too, with computers, tills, display lighting and refrigeration running throughout opening hours rather than intermittently. And the operating pattern is different: a commercial system runs at full load for the whole working day rather than cycling gently, which affects both sizing and the choice of equipment. Retail spaces with display lighting and food service areas with cooking equipment need more still, and should be treated as special cases rather than sized from a general rate. This is an estimate for scoping and budgeting. Any commercial installation of consequence needs a proper load calculation from an engineer, because getting it wrong is expensive both in equipment and in running cost.
How to use Commercial BTU Calculator
- Enter room area in m² or ft²
- Set ceiling height, sunlight exposure, and number of occupants
- See recommended BTU, kW, and AC unit type
Frequently Asked Questions
- How is commercial sizing different from residential?
- Occupant density, equipment density and operating hours are all higher. A commercial space packs more people and more running equipment into the same floor area, and the system runs at load all day rather than cycling gently as a home system does.
- How many BTU per square foot for an office?
- This calculator uses 32 BTU/h per square foot as a general commercial figure. Dense open plan offices, server rooms and retail spaces with heavy display lighting run higher, and should be assessed individually rather than from a general rate.
- Should I add for the number of staff?
- The commercial rate already assumes higher occupancy than a home. If your density is unusually high, such as a call centre or a classroom, add capacity on top or have a proper load calculation done.
- Is this enough to specify a system?
- No. It is suitable for scoping and budgeting. Commercial installations need a proper load calculation covering local climate, building construction, orientation, ventilation requirements and internal gains, which no per-square-foot rate can substitute for.
- What about a restaurant or a commercial kitchen?
- Treat those separately. Commercial cooking equipment produces heat on a completely different scale from domestic appliances, and the ventilation requirements are driven by regulation rather than comfort.
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