AC BTU / Cooling Load Calculator (UAE)
Estimate the cooling load for a room in the UAE and the split or window AC size (1 – 3 ton) that matches it.
How the AC BTU calculator works
Cooling load depends mainly on floor area, ceiling height, sun exposure, insulation, occupants and heat-producing appliances. In the UAE climate, where outdoor design temperatures reach 45 °C or more and humidity is high on the coast, engineers typically allow around 600–700 BTU/h per square metre of floor area for residential rooms with standard 2.8–3 m ceilings, compared with 400–500 BTU/h per m² in temperate climates. This calculator starts from that Gulf-specific figure, scales it for taller ceilings, then applies multipliers for sun exposure and insulation and adds a fixed allowance per occupant and for kitchen or office equipment.
| Room area (typical UAE apartment, 2.8 m ceiling) | Estimated load | Common unit size |
|---|---|---|
| Up to 14 m² | 9,000–11,000 BTU/h | 1 ton |
| 14–20 m² | 12,000–18,000 BTU/h | 1.5 ton |
| 20–27 m² | 18,000–24,000 BTU/h | 2 ton |
| 27–33 m² | 24,000–30,000 BTU/h | 2.5 ton |
| 33–40 m² | 30,000–36,000 BTU/h | 3 ton |
Why oversizing is a problem
An oversized unit cools the air quickly and cycles off before it has removed enough moisture, which leaves rooms feeling clammy — a common complaint in Dubai, Sharjah and Abu Dhabi apartments. Frequent cycling also shortens compressor life and wastes electricity. An undersized unit runs continuously and never reaches set-point on the hottest afternoons. Aim for the size that matches the calculated load, rounding up only when the room is sun-facing or has high internal gains.
Units explained
1 ton of refrigeration = 12,000 BTU/h ≈ 3.517 kW of cooling. Manufacturers list nominal capacity in BTU/h or kW on the nameplate; the number in the model code (e.g. "18" in MSGS18VF or MST1-18) usually indicates 18,000 BTU/h, i.e. 1.5 ton.
Related products & guides
FAQs
How many BTU do I need per square metre in the UAE?
As a rule of thumb, 600–700 BTU/h per m² for rooms with 2.8–3 m ceilings in the UAE, rising for sun-facing rooms, kitchens and top-floor spaces. Temperate-climate guides quoting 400–500 BTU/h per m² underestimate Gulf conditions.
Is a 1.5 ton AC enough for a 20 m² bedroom?
Usually yes for a shaded or average bedroom. For a west-facing bedroom with large glazing, or a top-floor room, a 2 ton unit may be needed. See our guide 1.5 ton vs 2 ton.
Does ceiling height change the AC size?
Yes. A 3.5 m ceiling holds about 25% more air than a 2.8 m ceiling; the calculator scales the load by volume for ceilings above 2.8 m.
Should I round up or down?
Round to the nearest standard size (1, 1.5, 2, 2.5, 3 ton). Round up only when the room has high solar gain or internal heat; oversizing reduces dehumidification.
