What size AC is needed? A simple guide in tons
AC tons by room size for Saudi summers: 1 ton up to about 11 m², 1.5 ton for a standard bedroom, 2 ton for a living room, and when to go one size up.
For a standard bedroom of about 11–17 m² in Riyadh, Jeddah or Dammam, a 1.5 ton AC (18,000 BTU/h) is the safe size. Sizing tables used for Gulf homes work out to roughly 1,000 BTU/h per m² of floor area, far more than in milder climates, because summer maximums in Saudi cities reach 44–47°C. On top of that, a room with strong afternoon sun or a hot roof above needs one step more.
Split units in Saudi shops are usually listed by BTU/h: 12,000, 18,000 and 24,000 BTU/h correspond to 1, 1.5 and 2 tons (1 ton equals 12,000 BTU/h). The cooling capacity on the label, in BTU/h or kW, is the figure to compare between brands.
Quick reference
| Room area | Suggested size | Capacity | Typical room |
|---|---|---|---|
| Up to about 11 m² | 1 ton | 12,000 BTU/h | Small bedroom, study, maid's room |
| 11–17 m² | 1.5 ton | 18,000 BTU/h | Standard bedroom |
| 17–20 m² | 1.5–2 ton | 18,000–24,000 BTU/h | Master bedroom |
| 19–23 m² | 2 ton | 24,000 BTU/h | Living or dining room |
| 23–33 m² | 2.5 ton | 30,000 BTU/h | Open-plan living area, majlis |
Above about 33 m², two units at opposite ends of the room, or a ducted system, usually cool more evenly than one large wall unit. When a room falls near the top of a range, the larger size is the safer choice.
This table is the cautious end of the scale. Some calculators from Saudi manufacturers give lower figures for shaded, well-insulated rooms: Zamil's calculator, for example, puts a 4 × 4 m bedroom for two people at about 10,000 BTU/h, which rounds up to a 12,000 BTU/h unit. The difference comes from sun, roof, insulation and glazing, so the installer should confirm the size on site.
How to work out the size
- Measure the room. Length × width in metres: a 3.5 m × 4.5 m bedroom is about 16 m².
- Find the row in the table. 16 m² falls in the 11–17 m² row: 1.5 ton.
- Check the conditions below. If any apply, go one step up. The same room on a top floor with a west-facing window becomes 2 ton.
- Read the label. Compare the BTU/h or kW on the specification sheet, not only the size printed on the box.
Only the space the AC has to cool counts, but an open kitchen or corridor without a door is part of that space. The AC size calculator runs these steps with the adjustments for sun, floor, people and kitchen; for Saudi summers the result is best read together with the table above.
Go one size up when
- Strong afternoon sun. West- and south-facing walls and large glass windows heat up from noon to sunset, exactly when cooling is needed most. A common rule of thumb is to add about 0.5 ton.
- Top floor or under the roof. A roof in summer heats the ceiling below it all day. A room that would take 1.5 ton lower down often needs 2 ton at the top.
- High ceiling. Sizing tables assume a ceiling of about 2.8 m. Double-height halls and mezzanines in villas need more.
- Several people. A family room or majlis that is often full runs warmer.
- Open kitchen. Cooking adds heat, so an open-plan living area with a kitchen needs the larger size.
Why not just buy bigger?
A larger unit costs more to buy and install, and it does not always feel better. An oversized non-inverter unit reaches the set temperature fast and switches off before it has removed the moisture. In humid weeks on the coast, in Jeddah or Dammam, that leaves the room cold but clammy, and constant on-off cycling wears the compressor.
An undersized unit runs at full power all afternoon, never reaches the set temperature, and pushes up the electricity bill. Inverter units slow down instead of switching off, so they cope better with a slightly larger size and use less power once the room is cool. With the residential tariff of 18 halalas per kWh up to 6,000 kWh a month and 30 halalas above that, plus 15% VAT, the AC electricity cost calculator helps compare running costs before buying.
Split, ducted or window?
- Wall-mounted split: quiet indoors, inverter models widely available, needs an outdoor unit with space around it. The usual choice for single rooms.
- Ducted or concealed: hidden above a false ceiling, cools several rooms or a large space through grilles. Common in villas; needs access panels for service.
- Window: lower purchase and installation cost, louder, needs a wall opening of the right size.
In rented apartments and compounds, the landlord or building management may need to approve a new outdoor unit or a new wall opening. That is worth checking before buying.
What it costs
Split units listed on a Saudi price-comparison site in January 2026 cost about SAR 1,250–1,900 for 12,000 BTU/h, SAR 1,600–2,950 for 18,000 BTU/h and SAR 2,600–3,350 for 24,000 BTU/h, depending on brand and features. Installation of a split unit in Riyadh is typically about SAR 250–450, including the bracket or base, about 3 m of copper pipe and a test run; longer pipe runs, cassette and ducted units cost more. A larger unit may need a dedicated circuit, which is work for an electrician.
A good installer confirms the size after seeing the room. The page for AC installation explains what is included, and one request on khalasna brings up to 5 quotes from installers in the area, for example in Riyadh.
Frequently asked questions
What size AC is needed for a 3 x 4 metre room?
A 3 x 4 m room is 12 m², which falls in the 1.5 ton range (18,000 BTU/h) on the cautious Gulf table. A shaded, well-insulated room on a lower floor may manage with 1 ton (12,000 BTU/h); a west-facing or top-floor room should not go below 1.5 ton.
Can one AC cool two rooms?
Not well with a wall-mounted unit. Cold air does not travel reliably through doors and corridors, so the far room stays warm. Separate units, a multi-split system or a ducted unit with grilles in each room work better.
How many BTU is 1 ton?
1 ton of cooling equals 12,000 BTU/h, or about 3.5 kW. A 1.5 ton unit is 18,000 BTU/h and a 2 ton unit 24,000 BTU/h, which is why shops list them as 12,000, 18,000 and 24,000 units.
Is 2 ton too big for a bedroom?
For a shaded bedroom under 17 m², usually yes, especially with a non-inverter unit that cycles on and off and leaves the room humid. It makes sense for a large master bedroom, a top-floor room or a room with strong afternoon sun.
Is an inverter AC worth it in Saudi Arabia?
Usually yes, because the AC runs many hours a day for most of the year. Inverter units cost more to buy but slow down instead of switching on and off, which lowers running costs once the room is cool.