How To Compare Air Conditioners While Shopping

Looking at air conditioners on the market may leave you wondering exactly what it is you'll be buying. A lot of concepts are tossed around. Does an air conditioner really weigh a ton? (No.) What's a BTU? Why might you need a plumber to help you install one?

The answers are actually straightforward, but it takes a little industry knowledge to appreciate what it is you'll be buying. Let's take a look at some key concepts you should study before you shop for air conditioners.

Tonnage and BTUs

These are, oddly enough, measurements of the exact same thing. If you want to know the output of an A/C unit, it's going to be measured in terms of either tons or BTUs. In fact, it's possible you'll see both listed for a system.

Tonnage and BTUs are completely interchangeable once you know the math. A single ton of air conditioning capacity counts the same as 12,000 BTUs. A BTU is a British Thermal Unit, and one BTU is equivalent to the amount of energy it takes to translate roughly 1000 joules or approximately 0.25 calories of energy into an action, in this, case cooling.

A potentially better way to think of output is in terms of how much space will be cooled. Roughly every 250 feet of empty air in a room will require 12,000 BTUs to cool. If there is anything in a room that produces heat, such as a stove or a heavily utilized computer, add 1,200 BTUs per item. Add a further 600 BTUs of cooling per person in a room.

Anything over 5 tons or 60,000 BTUs is considered a commercial-grade setup. 12,000 BTUs of energy usage should translate to about 3.5 kW of electrical consumption.

Efficiency Ratings

The Seasonal Energy Efficiency Ratio, more commonly styled as an A/C unit's SEER rating, is what's commonly listed on the yellow "Energy Guide" tag that's attached to most air conditioners sold in the U.S. Thirteen is the lowest acceptable SEER rating, although higher is always better. Most modern setups max out at a rating near 22. In order to get the most bang for your buck, you'll want to only check out air conditioners rated around 19 or higher.


Once a system has pulled water from the air, it has to go somewhere. You may need to hire a plumber to install drainage lines for your A/C setup.

To learn more, talk to a company such as Albert Lee Appliance.