How to Choose the Right BTU for Your Room
A practical BTU calculator guide for Philippine room sizes, with a sizing table and step-by-step method for common room types.
Understanding BTU and Horsepower in Philippine Context
BTU (British Thermal Unit) measures how much heat an aircon removes per hour. In the Philippines, units are most commonly sold by horsepower (HP), but HP and BTU are directly related: 1.0 HP equals approximately 9,000 BTU, 0.75 HP equals 7,000 BTU, and 0.5 HP equals 5,000 BTU.
Philippine sellers and technicians default to HP because it maps to the common residential unit sizes: 0.5 HP for small bedrooms, 1.0 HP for standard bedrooms and small living rooms, 1.5 HP for medium living areas, and 2.0 HP for large living rooms and master bedrooms.
BTU Sizing Table for Philippine Rooms
As a starting guide: rooms up to 10 sqm need 5,000 BTU (0.5 HP); 11–15 sqm need 7,000 BTU (0.75 HP); 16–20 sqm need 9,000 BTU (1.0 HP); 21–30 sqm need 12,000 BTU (1.5 HP); 31–45 sqm need 18,000 BTU (2.0 HP). These figures assume a standard ceiling height of 2.5 meters and typical Philippine sun exposure.
For rooms that receive direct western afternoon sun — a common issue in Metro Manila high-rise condos — add 15% to the base BTU. For rooms occupied by more than two people regularly, add 600 BTU per additional person. Rooms with a kitchen or adjacent cooking area should also add 4,000 BTU to account for heat generated by cooking.
Common Sizing Mistakes and How to Avoid Them
Oversizing is the most common mistake. A 2.0 HP unit installed in a 15 sqm bedroom will cool the room too rapidly, switching off before moisture is removed from the air. The room will feel cold but sticky — and the frequent compressor cycling accelerates wear on the unit.
Undersizing is less common but equally problematic. An undersized unit runs continuously at full capacity, never quite reaching the set temperature on very hot days, consuming maximum electricity while delivering subpar comfort. Always use the room's actual usable floor area — not the stated unit size on the property listing — as these often differ by 10% or more.
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