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What's a BTU?

Updated: 2 days ago

In the market for a new air conditioner? If you are, you’ve definitely seen the term “BTU” floating around, and chances are, you’re also wondering what on earth it means.

A/C unit outside

What does BTU mean?

BTU (sometimes written as BTUH), which stands for British Thermal Unit per Hour, is a unit of measurement which measures the amount of heat an air conditioner can remove from the air within one hour. To paint a more digestible picture, 1 BTU is the required energy to heat or cool a pound of water by 1 Fahrenheit at sea level.

Understanding what a BTU is is very important when choosing the best air conditioner to fit your and your home’s needs.

Why are BTUs important when looking for an AC?

As you search for a new air conditioner, paying close attention to BTUs is key as it shows you just how powerful the machine is. It’s important to consider BTU when comparing air conditioners.

An air conditioner that is too weak for your square footage will not only simply not have the adequate power to cool down your home, causing it to run constantly to try to reach the temperature set on the thermostat. Consequently, your energy bill could soar due to its constant running, with no fruits as your home will probably have uncomfortably uneven temperatures throughout.

An air conditioner that is too strong will cycle too quickly, causing it to shut on and off very frequently while not cooling properly, which is not only wasted energy but can cause damage, as air conditioners shouldn’t be cycling at high rates. Likewise, they cannot properly dehumidify, as the cycle often will run too quickly. This can leave you with a humid and uncomfortable environment, while also causing some pain to your energy bill due to its constant cycling.

Why use BTU?

BTU is the measurement of heat loss or gain, making it the ideal measurement when rating the performance of air conditioners, furnaces, grills, or any other appliance that extracts or emits heat. Although we may think of air conditioners as machines that simply pump cold air into our homes, they actually extract heat from the air instead.

In order to best evaluate the needs of your space and match you with the perfect unit to satisfy your air conditioning needs, BTU is the perfect metric to do so, and understanding it can save you a lot of headaches and coins in the long run!

How many BTUs do I need?

Now that we understand what a BTU is and its importance, it’s about time to figure out how to put that knowledge to practical use.

It’s recommended that an air conditioner has the power of 20 BTUs for every square foot of space. From there, it’s simple! Just multiply the square footage of the room or home that you’re looking to cool by 20, and you will have a rough idea of a BTU measurement to work off of when searching for a new unit.

To be more precise, professionals will often measure taking ceiling height, doorways, and windows into account. However, knowing a general estimate like the above is still a good measurement to go off of.

Some examples:

​Square Footage

​BTUs Required


5,000 BTU


12,000 BTU


18,000 BTU


23,000 BTU


30,000 BTU


34,000 BTU

Call us

Have questions about BTU, power, air conditioner installation, or anything in between? Please, don’t hesitate in giving us a call here at Tri-Point Refrigeration. We’re happy to hear from you and are excited to help you along the way. Take advantage of our maintenance plan and warranty when you choose to go with us for a new unit purchase and installation!

For a direct line to any of our employees ready on the line to help you, please call…(512) 651-4565 for our Austin, Texas community (806) 686-0050 for our Lubbock, Texas community. Or check out our website at

Image by <a href="">Freepik</a>


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