Air conditioner Complete selection and installation guide

Why You Must Know Room Area Before Selecting an Air Conditioner

When it comes to buying an air conditioner, one of the most common questions in every customer’s mind is:
👉 “What size of AC is right for my room?”

Most people rely on sellers, friends, or other customers’ experiences. But here’s the truth: an incorrectly sized air conditioner will either waste electricity or fail to cool your room properly.

That’s why understanding the room area and cooling requirements is crucial before you make your purchase.

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Why AC Sizing Matters

• If AC capacity is higher than required:

  • Excessive power consumption

  • Cooling cycle stops early → humidity not removed → damp and clammy feeling

  • Lower efficiency and shorter equipment life

• If AC capacity is lower than required:

  • Room will never reach comfortable cooling

  • AC runs continuously → higher electricity bills

  • Equipment wears out faster

Thus, the right-sized AC ensures effective cooling, proper dehumidification, and optimal electricity use.

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Functions of an Air Conditioner

1. Cooling – lowers the room temperature to the desired level

2. Dehumidification – removes excess moisture from the air

If an oversized AC is installed, the room may cool quickly but without sufficient dehumidification, leaving it cool but humid, which feels uncomfortable.

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How to Measure Room Area

• Square or rectangular room: Length × Width

• Triangular room: (Length × Width) ÷ 2

• Irregular-shaped room: Divide into smaller sections, calculate area, then sum them up

For accurate measurement, take the help of an AC technician or sales expert.

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Cooling Capacity Requirement

Air conditioners are rated in BTUs/hour (British Thermal Units).

• 1 Ton of cooling ≈ 12,000 BTU/hour

Here’s a simplified Room Size vs AC Size Guide:

Room Area (sq. ft.) BTU/hr Required AC Size (Tons) 100 – 150 5,000 0.5 ton 150 – 250 6,000 0.5 ton 250 – 300 7,000 0.75 ton 350 – 400 9,000 1 ton 450 – 550 12,000 1 ton 700 – 1,000 18,000 1.5 ton 1,000 – 1,200 21,000 1.75 – 2 ton 1,200 – 1,400 23,000 2 ton 1,500 – 2,000 30,000 2.5 ton 2,000 – 2,500 34,000 3 ton
Additional Factors Affecting AC Capacity

1. Room Orientation & Sunlight

   • Shaded rooms → reduce capacity by 10%

   • Sun-facing rooms → increase capacity by 10%

2. Number of Occupants

   • Standard: 2 people

   • Add 600 BTU/hour per extra person

3. Kitchen Usage

   • Cooking adds extra heat load

   • Increase capacity by 4,000–5,000 BTU/hour (≈30%)

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Indoor & Outdoor Unit Installation

Indoor Unit

• Install at 7–9 ft height for effective airflow

• Place where air distributes evenly

• Ideally above the bed (but not blowing directly on the body)

• Adjust louvers for better airflow

Outdoor Unit

• Install in an open space (terrace/external wall) with free airflow

• Position above indoor unit for better refrigerant flow

• Keep distance ≤15 meters between indoor & outdoor units

• Ensure easy accessibility for maintenance

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Single-Stage vs Two-Stage Compressor ACs

• Single-Stage AC:

  • Works only at full capacity

  • Less efficient, higher energy bills

• Two-Stage AC:

  • Operates at both high and low levels

  • Adjusts cooling as per outside temperature

  • Saves electricity and provides more comfort

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Conclusion

Choosing the right size of air conditioner is not just about comfort, but also about energy savings, efficiency, and long-term durability. By measuring your room size, calculating BTU requirements, and considering additional factors (sunlight, occupants, kitchen use), you can select the most suitable AC for your home.

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Disclaimer

The above information is for educational purposes only. Actual AC size requirements may vary based on room insulation, ceiling height, climate conditions, and manufacturer specifications. Always consult a qualified HVAC technician before making your final purchase.

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