Methodology
The goal is to make it obvious which numbers come from official sources and which are our own estimation choices.
Methodology reviewed: 23 September 2026
AC capacity
The starting point is the empirical Saudi TVTC training rule: room volume in m³ × 300 ≈ BTU/h. We then apply modest site heuristics for city/climate, sun, insulation, windows, occupancy, top floor and kitchen/high internal heat.
| Factor | Multiplier / adjustment |
|---|---|
| City | Riyadh 1.05; Jeddah 1.03; Dammam/Khobar 1.04; Makkah 1.06; Madinah 1.05; Taif 0.88; Abha 0.78; other 1.00 |
| Sun | Mostly shaded 0.95; average 1.00; strong direct sun 1.08 |
| Insulation | Good 0.90; average 1.00; weak/unknown 1.12 |
| Windows | Small 0.97; average 1.00; large/many 1.08 |
| Top floor / sun-exposed roof | × 1.08 |
| Kitchen / high internal heat | × 1.12 |
| Occupants above two | +600 BTU/h per person |
Stress-test the assumptions
This does not create a new engineering answer. It shows how the disclosed site multipliers move the raw volume-based load. Change one assumption at a time to see which inputs drive the estimate.
Standard-size rounding
After estimating load, we round upward to the first practical size in our list: 9,000; 12,000; 18,000; 24,000; 30,000; 36,000; 42,000; 48,000; 54,000; 60,000 BTU/h.
Electricity cost
The site applies residential energy tiers piecewise: through December 2026, SAR 0.18/kWh up to 6,000 kWh/month and SAR 0.30 above it; from January 2027, SAR 0.21 and SAR 0.33 respectively. Incremental AC cost is the change in the energy charge with additional AC load, so unchanged service fees cancel out. The whole-home estimate separately includes the 2026 meter reading fee (SAR 10–30 by breaker) or the 2027 fixed charge (SAR 70–100 by breaker, prorated by bill days/30). See official sources.
VAT and efficiency comparison
The optional VAT switch adds 15% as the current standard Saudi VAT rate where applicable. Efficiency comparison uses annual kWh entered from product label data; we do not assume a fixed “inverter savings percentage.”
Limits
- Not an engineering design or compliance certificate.
- No brand recommendation or product price is implied.
- Calculator inputs run locally in the browser.
- Official sources and assumptions are reviewed when requirements change.