AC BTU Calculator - Calculate Cooling Capacity in BTUs
Are you trying to find the correct BTU rating for your air conditioner? BTUs (British Thermal Units) are the most common unit of measure for cooling capacity, whether you're shopping in the U.S., UK or Canada.
Our BTU Calculator will show you exactly how many BTUs you need for your room, which will keep you operating at an optimal cooling level.
AC BTU, Watts & kW Calculator
Room size (sq.ft.) vs BTU requirement per hour :
What is a BTU in Air Conditioning?
BTU is short for British Thermal Unit. It is the amount of energy that it takes to cool or heat one pound of water one degree Fahrenheit. In air conditioning, you can think of BTUs as the cooling power — more BTUs = more cooling.
How We Determine Your BTU Requirements?
We take into consideration the following:
1. Room Size (The room dimensions are length × width x height)
2. Sunlight exposure (South-facing rooms = higher heat)
3. Number of windows, people, and electronics
4. Geographical climate (hot areas vs cold areas)
Example:
For a 300 sq ft room with a high level of sunlight and 3 people, you'll need approx. 8,000 to 10,000 BTU/hour cooling.
Conversion Ratio:
If you already know your tonnage:
1 Ton = 12,000 BTUs/hour
More Options for More Precision:
- Toggle between sq ft / sq m
- Ceiling height can be varied
- Add appliance heat load
Common Problems:
- If you have a high BTU unit for a small space = overcooling + dehumidification
- If it is too small = inefficiency and wearing out the system
Pro-Tip:
If you have a room with a lot of foot traffic or more appliances, don’t forget to add 600 BTU for extra person(s), or add 500 BTU for each appliance.
Summary:
Our AC BTU Calculator is the most accurate cooling estimate taking into account real-world factors. Try it out and hopefully you will find an AC option for you!
Frequently Asked Questions
Q: How many BTUs do I need for 400 sq ft?
A: Typically you will need 9,000 - 10,000 BTUs / hour depending on sun exposure & height of ceiling.
Q: In BTUs bigger is better right?
A: No. An oversized AC will be short cycling too fast without removing enough moisture in your space.
