What Is BTU on an Air Conditioner, and Why Does It Matter?

If you're shopping for a new AC for this summer, the initials BTU seem to come up all over the place. But what is a BTU, and how exactly should it factor into your choice of air conditioner? We're going to give you a quick rundown of everything you need to know about those three little letters, and an easy way to determine the best BTU level for your AC!

What Does BTU Stand For?

BTU, meaning British Thermal Unit, is an expression of the amount of energy needed to raise one pound of water by one degree Fahrenheit while at sea level. For air conditioners, this rating tells you how many BTUs per hour the machine can remove from the indoor air. The higher the BTU rating, the more high-intensity the cooling, and the larger the space that can be cooled. Available ratings range from 5000 BTU ACs all the way up to 12,000 BTU ACs and higher.

Do Higher BTUs Use More Electricity?

Yes, but there's more to an AC's efficiency than just electricity use. Different spaces require different BTU levels. Of course cooling a larger space is going to require more power than cooling a smaller space, but skimping on necessary BTU power can lead to issues in other areas.

Is It Better to Oversize or Undersize an AC?

Doing either can lead to problems! If your AC BTU rating is too high for the room you're trying to cool, the unit will be cycling on and off constantly, and could lead to condensation buildup that creates a muggy, humid environment. If you use an AC with a BTU rating that's too low, the unit will be struggling to keep the room cool and may not ever be able to cycle off, making it extremely energy-inefficient. It behooves you to go with a BTU level as close to “just right” as possible.

What Does DOE BTU Mean on a Portable AC?

When an air conditioner is cooling a room, the unit emits some heat. Unlike a window or wall AC, a portable air conditioner sits entirely inside a room, and some of the emitted heat ends up dissipating into the very space it's trying to cool. The DOE BTU rating takes into account the heat emitted by the portable AC unit, giving a more accurate "real-feel" rating. This means you can be sure your AC unit is accurately rated, which means better cooling and greater efficiency.

How Can I Do a Calculation of BTU Needed to Cool My Space?

Calculating AC size is mostly done by measuring the dimensions of the space that needs cooling. However, other factors come into play such as which floor of the building the room is on, how many people are typically in the space, and more. The good news is, we've got a BTU calculator to make it as simple as possible! Simply punch in some numbers, answer a few questions, and in seconds we'll tell you the ideal BTU level for your space!

Is the BTU level of your current AC right for your space, or could it be better? Whether you need a window AC, wall unit or portable unit, taking a few minutes to determine BTU for air conditioner units is vital to keeping your space cool and comfortable all season long!