Commercial spaces carry far heavier internal loads: people (~600 BTU each), computers (~400 BTU each) and equipment. Server rooms are sized on equipment watts, not floor area.
Estimate only — confirm with a professional load calculation.
| Recommended unit | — |
| Tonnage equivalent | — |
Commercial spaces carry internal loads homes don’t, which is why this calculator applies an uplift and asks about equipment separately:
Two field practices worth copying: size at realistic peak occupancy (a Saturday afternoon, not a Tuesday morning), and above roughly 5 tons prefer two units over one for redundancy and evener coverage.
Dedicated pages tune these factors per space:
Retail shop · Restaurant · Gym · Salon · Server room · Classroom
For server rooms, ignore floor area entirely and size on equipment watts — the server-room guide shows the method.
Size on the IT load, not the floor area: every watt of equipment power becomes ~3.41 BTU/hr of heat. A 5 kW rack needs ~17,000 BTU/hr (1.4 tons) of dedicated cooling plus redundancy.
About 400–600 BTU/hr per seated person (sensible + latent). In dense spaces — meeting rooms, call centres, classrooms — occupancy drives the load more than floor area, which is why this tool asks for headcount, not just square footage.
Commercial spaces carry loads homes don't: constant door-opening infiltration from customer traffic, display and task lighting running all day (every watt becomes heat), denser occupancy, and equipment from espresso machines to POS terminals. That's the commercial uplift this calculator applies.
For high-occupancy or equipment-heavy spaces, internal loads dominate, so size on people plus equipment watts rather than area alone. Server rooms are the extreme case — size purely on equipment watts; see the server-room guide.
commercial internal loads follow the ASHRAE Handbook — Fundamentals; data/server rooms per ASHRAE TC 9.9 — ASHRAE. See the server-room guide. See our full methodology.