Got an AC installed but still not cool enough? Most likely the room size was miscalculated. If you only match the room area and ignore west-facing sun, high ceilings, and other heat sources, cooling suffers. This article walks through basic AC terminology, step-by-step room-size calculation, matching AC specs, and practical tips for common Taiwan scenarios.
Room Size Calculation: 3 Key AC Terms First
Cooling Capacity: how much heat removed per hour, in kW. 1kW ≈ 860 Kcal/h ≈ 3412 BTU/h.
Power Consumption: actual electricity used while running, also in kW but different in meaning.
CSPF (Cooling Season Performance Factor): average efficiency across temperatures and loads; higher CSPF, near Tier 1, means lower power use.
Room Area Formula
Formula: length (m) × width (m) × 0.3025 = area in ping. In Taiwan's climate, budget about 0.6–0.8 kW cooling capacity per ping.
Cooling Capacity vs. Room Size
| Room (ping) | Suggested cooling capacity | Suggested tonnage |
|---|
| 2–3 ping | ≈ 2.0–2.3 kW | ≈ 0.6 ton |
| 3–4 ping | ≈ 2.5–2.8 kW | ≈ 0.8 ton |
| 4–5 ping | ≈ 3.2–3.6 kW | ≈ 1.0 ton |
| 5–6 ping | ≈ 3.8–4.2 kW | ≈ 1.2 ton |
| 6–8 ping | ≈ 4.5–5.0 kW | ≈ 1.5 ton |
| 8–10 ping | ≈ 6.0–7.0 kW | ≈ 2.0 ton |
Heat Sources & Capacity Adjustments
High ceiling: 0.7–0.8 kW per ping.
West-facing sun: 0.7–0.8 kW per ping.
Top-floor addition: 1.0 kW per ping.
Why Room Size Matters? Buying Too Big or Too Small
Too small: slow cooling, shorter compressor life, higher power use.
Too large: frequent on/off, unstable temperature, weaker dehumidification, higher upfront cost.
Conclusion
Many buy AC by brand or price alone, but the real key is correct room-size calculation. Acerpure CHILL SAC2 PINOKI smart inverter AC brings cool, fresh air home. Acerpure also offers an AC purchase calculator to size your home's ideal unit in one step!