AC Room Size Calculator

Find the perfect AC unit size based on room dimensions and environmental factors.

Room Dimensions

Length (ft)

Width (ft)

Ceiling Height (ft)

Occupants

Sunlight

Is it a Kitchen?

Recommended Unit Size

Finding the right AC?

Provide your room dimensions and environmental conditions to determine the appropriate BTU rating for your next AC unit.

Overview

Sizing an air conditioner correctly is the difference between a comfortable home and an expensive electricity bill. An AC that is too small will run constantly without cooling the room, while an AC that is too large will cycle on and off too quickly, failing to remove humidity. This calculator uses the Energy Star recommended cooling requirements based on square footage, adjusted for real-world factors.

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Pro Tips

Always round up when choosing between two AC sizes to ensure you have enough capacity for the hottest days.
Portable AC units are generally less efficient than window or split units; you might need higher BTUs for the same square footage.
Check the EER (Energy Efficiency Ratio) of units; higher EER means lower operating costs.

Fun Facts

"BTU stands for British Thermal Unit—the amount of energy needed to raise the temperature of one pound of water by one degree Fahrenheit."
"A typical 5,000 BTU unit is usually sufficient for a 150 sq ft room, while a 12,000 BTU unit handles up to 550 sq ft."
"If your ceiling is higher than 8 feet, you should increase the cooling capacity by 25%."

Formula: Base BTU = (Area × 25) [for 8ft ceilings]; Adjustments: +600 per person > 2, +4000 for Kitchen, +/- 10% for Sunlight.

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