Air Conditioner Size Calculator

Room size to HP, cooling capacity and summer cost

Quick Answer

Air Conditioner Size Calculator: Room size to HP, cooling capacity and summer cost. 1 HP ≈ 2500W cooling · base need = area × 150–220 W/㎡.

Room area (㎡)

Ceiling (m)

Occupants

West-facing sunTop floor

Recommended size

大1.5P

Need 3,600W → 大1.5P（3,600W）

Steps

1Base: 20㎡ × 180W/㎡ × (2.8/2.8 height adj)
2Total ≈ 3,600W → round up to 大1.5P (3,600W)
3Rule: 1P ≈ 2500W cooling capacity

Area quick reference (2.8m ceiling, no sun)

Area	Size	Area	Size
10㎡	1P	25㎡	2P
12㎡	1P	30㎡	2P~2.5P
15㎡	1.5P	35㎡	2.5P
18㎡	1.5P	40㎡	3P
22㎡	1.5P~2P	50㎡	3P~5P

💡 "Buy bigger not smaller": an undersized AC runs non-stop without reaching setpoint, wasting energy. Choose inverter (变频) for rooms used >4h/day — saves ~30% vs fixed-speed. Grade-1 efficiency (APF≥5.0) pays back the price gap in 2-3 summers of heavy use.

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How to Use

Enter scenario values: fill real-life numbers into the Air Conditioner Size Calculator (defaults work for a quick try).
Instant results: everything computes live, no button needed.
Read the advice: results come with practical tips, reference standards and pitfalls.
Compare options: adjust parameters to compare choices side by side.

Key Points

Air Conditioner Size Calculator is a free online everyday life tool — open and use, no sign-up.
All calculations run locally in your browser; your data never leaves the device.
Key capability: Room size to HP, cooling capacity and summer cost.
Results come with formulas and reference tables so you can verify every number.

Formula & How It Works

AC sizing

1 HP ≈ 2500W cooling · base need = area × 150–220 W/㎡

1HP 10–15㎡ · 1.5HP 15–22㎡ · 2HP 22–32㎡ · 3HP 32–45㎡

Add 10–15% each for west sun / top floor / large windows

FAQ

How do I use the Air Conditioner Size Calculator?

Open the page and fill in the input fields — results update automatically. Room size to HP, cooling capacity and summer cost.

Are the results accurate?

Yes. Standard formulas and conversion factors are used and verified.

Is it free? Do I need to sign up?

Completely free. No registration, login or download required.

Does it work on mobile?

Yes. The responsive design works on phones, tablets and desktops.

Is my data saved?

No. Everything runs locally in your browser.

Related Guides

Source & Updates

Based on common formulas and industry conventions. Last updated: 2025-07

Last updated: 2026-08-04

Formulas and content on this page are reviewed by the YiJianSuan team. For reference only — official sources prevail.

Cite this page: YiJianSuan. Air Conditioner Size Calculator[EB/OL]. https://www.yijiansuan.com/en/c/life/air-conditioner

Results provided by this tool are for reference only and do not constitute professional advice.