Aircond HP Guide: What Size for Your Room

Choosing the right aircond horsepower for your room is the single most important decision in the buying process. An undersized unit runs at full load all day, never reaches the target temperature, and drives your TNB bill up. An oversized unit short-cycles — switching on and off repeatedly — which wastes energy, creates uneven cooling, and shortens the compressor's lifespan. This guide gives you a clear room size to HP formula for Malaysian conditions, plus the full LG DUAL Inverter range with pricing.

The basic formula

The general calculation for Malaysian homes uses BTU (British Thermal Unit) requirements based on room size, then converts to HP.

Step 1: Calculate room area in square feet. Length (ft) x Width (ft) = Room area (sq ft).

Step 2: Multiply by 65 BTU per sq ft. This is the baseline for Malaysian climate — year-round tropical heat, standard 9-10 ft ceiling height, and moderate sun exposure.

Step 3: Adjust for conditions. Add 10-20% if the room gets direct afternoon sun, has large glass windows, is on the top floor, or has a ceiling higher than 10 ft. Subtract 10% if the room is shaded, has minimal windows, or is on a lower floor of a high-rise.

Step 4: Match BTU to HP. Use the conversion table below.

Quick room size to HP table

If you do not want to calculate BTU, use this simplified guide.

These are guidelines for standard Malaysian conditions. Adjust up if your room has specific heat factors.

Factors that increase cooling load in Malaysia

Seven conditions common in Malaysian homes that require you to size up by 0.5 HP.

Direct afternoon sun. West-facing rooms absorb significantly more heat between 2pm and 6pm. If the room has large west-facing windows, add 0.5 HP.

Top floor / no insulation above. The top floor of a landed house or the highest floor unit in a low-rise condo absorbs roof heat. This can add 15-25% to the cooling requirement.

Large glass windows or sliding doors. Floor-to-ceiling windows are common in Malaysian condos. Glass transmits heat faster than walls, so a room with extensive glazing needs more cooling capacity.

High ceilings. A room with a 12 ft ceiling has 20% more air volume than a room with a 10 ft ceiling. The aircond needs more capacity to cool the extra volume.

Kitchen heat. If the aircond cools an open-plan space that includes the kitchen, residual heat from cooking appliances adds to the load. Consider sizing up or using a separate unit for the kitchen area.

Many occupants. Each person generates approximately 400 BTU/hr of body heat. A living room that regularly hosts 6-8 people needs more capacity than the same room used by 2 people.

Electronic equipment. A home office with multiple monitors, a desktop PC and a laser printer generates measurable heat. Add 10% if the room has significant electronics.

The 6 LG DUAL Inverter aircond models

All LG airconds in this range use DUAL Inverter compressor technology with a 10-year warranty, Plasmaster ionisation, and R32 refrigerant.

Standard vs ARTCOOL: which to choose

The standard DUAL Inverter and ARTCOOL models share identical cooling performance at the same HP level. The difference is design: ARTCOOL replaces the white plastic indoor unit with a mirror-glass panel that blends into modern interiors.

The price premium is RM10/month — RM100 vs RM90 for 1.5HP, and RM130 vs RM120 for 2.5HP. If the indoor unit is mounted in a visible position (above the sofa, facing the bed), the ARTCOOL is worth the premium. For utility rooms, spare bedrooms and spaces where aesthetics are secondary, the standard model saves RM10/month.

Sample room calculations

Example 1: Master bedroom in a condo. Room measures 14 ft x 16 ft = 224 sq ft. Standard ceiling, no direct sun. 224 x 65 = 14,560 BTU. This falls in the 1.5 HP range. Recommendation: 1.5HP DUAL Inverter at RM90/month.

Example 2: Living room in a double-storey terrace. Room measures 20 ft x 18 ft = 360 sq ft. West-facing windows with afternoon sun. 360 x 65 = 23,400 BTU + 20% sun adjustment = 28,080 BTU. This exceeds 2.0 HP and needs 2.5 HP. Recommendation: 2.5HP DUAL Inverter at RM120/month.

Example 3: Child's bedroom. Room measures 10 ft x 12 ft = 120 sq ft. No direct sun, lower floor. 120 x 65 = 7,800 BTU. This is comfortably within 1.0 HP range. Recommendation: 1.0HP DUAL Inverter at RM80/month.

Example 4: Open-plan living and dining. Combined area measures 22 ft x 28 ft = 616 sq ft. High ceiling (12 ft), some west-facing glass. 616 x 65 = 40,040 BTU + 25% adjustment = 50,050 BTU. This exceeds any single wall-mounted split unit. Consider two units: a 2.5HP for the living zone at RM120/month and a 1.5HP for the dining zone at RM90/month.

Common HP mistakes to avoid

Buying 1.0HP for a master bedroom. Many Malaysian master bedrooms are 180-250 sq ft — too large for 1.0HP to cool effectively. The unit runs at full load all day, consumes more electricity than a correctly sized 1.5HP at variable speed, and never reaches target temperature. Size up to 1.5HP.

Buying 2.5HP for a small bedroom. An oversized unit cools the room in minutes, then shuts off. When the temperature rises slightly, it blasts on again. This short-cycling creates cold-hot swings, increases wear on the compressor, and uses more electricity than a correctly sized unit maintaining steady output.

Ignoring sun exposure. A shaded 300 sq ft room and a sun-blasted 300 sq ft room have very different cooling loads. Always account for window orientation and direct sunlight.

What is included on LG Subscribe

Every aircond on LG Subscribe includes free delivery, professional installation of both indoor and outdoor units, a 10-year compressor warranty, and annual servicing (chemical wash and performance check). You do not pay upfront and there is no deposit.

Plans run 60 months (5 years). At the end of the term, the unit is yours. You can also choose to upgrade to a newer model at that point.

Related reading

Next step

Not sure which HP your room needs? Send us your room dimensions and window orientation on WhatsApp. Our consultants will calculate the BTU requirement and recommend the right LG model — no guesswork, no overselling.