Comfort Cooling Load Estimator
A 20 m² bedroom with average sun, two people and a TV needs about 4.8 kW of cooling — 16,500 BTU/h, a 2.0 HP unit in Philippine market sizing. Running 8 hours a night on an inverter, roughly ₱2,600 a month at ₱12/kWh.
Enter the room, the sun, the people and the equipment. The estimator returns kW, BTU/h and the market HP size — and is honest about its limits: for offices and commercial spaces, use our full ASHRAE-method Office Cooling Load Calculator instead.
Your Room
Cooling Load Estimate
| Component | Value | Basis |
|---|
The Method
Screening load (envelope by sun band, plus people and equipment, plus 10% margin):
Market HP conversion (Philippine convention — check the spec sheet's actual BTU/h):
Method & Sources
- Envelope bands 150 / 200 / 250 W/m² — tropical screening values consistent with the Philippine installer rule of 1 HP per 10–14 m², and sense-checked against our full ASHRAE-method office calculator. They absorb walls, roof, windows and ventilation in one figure — that is what makes this a screening tool, not a design tool.
- Occupants 115 W each — ASHRAE Fundamentals heat gain for a seated person at rest (sensible + latent).
- 10% margin — covers door openings and the odd extra guest without encouraging oversizing.
- 1 HP ≈ 9,000 BTU/h ≈ 2.64 kW — Philippine market convention. The honest catch: oversized aircons short-cycle, dehumidify poorly and cost more to buy and run. Size to the load, not "one bigger to be safe".
- Running cost — assumes an inverter unit averaging ~50% of rated input once the room reaches temperature, with rated input ≈ cooling kW ÷ 3 (a typical EER for inverter splits). Non-inverter units typically use 25–35% more.
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Frequently Asked Questions
What HP aircon do I need for a 20 m² room?
With average sun, two occupants and a TV: about 4.8 kW / 16,500 BTU/h — a 2.0 HP unit. That sits inside the installer rule of 1 HP per 10–14 m². Strong afternoon sun pushes it up a size; a shaded ground-floor room drops one.
How is aircon HP related to BTU and kW?
Market convention: 1.0 HP ≈ 9,000 BTU/h ≈ 2.64 kW of cooling. So 1.5 HP ≈ 13,500 BTU/h and 2.0 HP ≈ 18,000 BTU/h. Always check the actual capacity on the spec sheet — "HP" is a loose label, not a measurement.
How much does an aircon cost to run per month?
A 2.0 HP inverter on bedroom duty (8 h/night, thermostat reached) averages roughly 0.9 kW — about 7 kWh a night, ₱2,600/month at ₱12/kWh. A non-inverter of the same size typically uses 25–35% more. Oversizing makes everything worse: short-cycling, poor dehumidification, faster wear.
Is this estimate good enough to buy on?
For one room with a split or window unit, yes. For offices, restaurants, server rooms or anywhere with dense occupancy or equipment, use the Office Cooling Load Calculator — it does fabric, ventilation and latent loads properly.
Cooling a Whole Building, Not a Room?
Above a few rooms, chilled-water fan coils beat a wall of split units — quieter, cheaper to run, one outdoor plant. That is what iZONE and a reversible iHEAT do together.
Ask About Whole-Building Cooling