**How to Calculate the Right Air Conditioner Size for Your Home**

Additional Factors to Consider

✔️ Number of Windows & Sun Exposure
Rooms that receive direct sunlight require a larger air conditioner capacity.

✔️ Number of Occupants
More people → more heat → higher HP required.

✔️ Electrical Equipment in the Room
TVs, computers, and lighting generate additional heat.

✔️ Ceiling Height
Higher ceilings require greater cooling capacity.

Simple Calculation Example

A room sized 200 sqft:

200 ÷ 400 = 0.5

Recommended: 1.5 HP (for comfortable and long-lasting performance)

Effects of Choosing the Wrong Air Conditioner Size

❌ Air conditioner too small → slow cooling, higher electricity bill
❌ Air conditioner too large → frequent on/off, energy wastage
❌ Unstable performance
❌ Shorter air conditioner lifespan

Conclusion

Choosing the right air conditioner size will:
✔️ Save on electricity bills
✔️ Provide even and consistent cooling
✔️ Extend the lifespan of the air conditioner
✔️ Avoid unnecessary repair costs

If in doubt, seek advice from an experienced electrical or air conditioning contractor.

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The capacity of split unit air conditioners is usually measured in HP (Horse Power). Common capacities available in the market are 1HP, 1.5HP, 2HP, 2.5HP, and 3HP.

VERSION 1

This calculation assumes the room is occupied by 2 people, has a 3-meter ceiling height, uncovered windows, and electrical equipment (including lighting) not exceeding 100W.

Air conditioner capacity = room area × 60 / 9000

required (length × width)

where:

room area = length × width (in square units)

Example:

A room measuring 16' × 20'. The air conditioner capacity calculation is:

room area = 16 × 20 = 320 square feet

air conditioner capacity = room area × 60 / 9000

= 320 × 60 / 9000 = 2.13 HP

Therefore, the suitable air conditioner capacity is 2.5 HP.

VERSION 2

Step 1

Calculate the room volume:
length (ft) × width (ft) × height (ft) = V ft³

Step 2

Multiply the volume by 6:

C1 = V × 6

Step 3

Estimate the number of people (P) using the room. Each person produces approximately 500 BTU/hour of body heat during normal daily activities.

C2 = P × 500 BTU/hour

Step 4

Add both values:

C1 + C2 = C (BTU/hour)

EXAMPLE

A room measuring 16' × 20' with a height of 9.8 ft (3 meters) and occupied by 2 people:

V = length × width × height

= 16 × 20 × 9.8 = 3136

C1 = V × 6

= 3136 × 6 = 18,816

C2 = P × 500 BTU/hour

= 2 × 500 = 1,000

C1 + C2 = C

= 18,816 + 1,000 = 19,816 BTU/hour
(within the range of 16,000 – 20,000 BTU/hour), equivalent to 2.0 HP

Reference

1 HP : 9,000 – 10,000 BTU/hour

1.5 HP : 12,000 – 15,000 BTU/hour

2 HP : 16,000 – 20,000 BTU/hour

2.5 HP : 22,000 – 27,000 BTU/hour

Therefore, the suitable air conditioner capacity is 2.0 HP.