## How do I tell the size in tons of my GE (General Electric) air conditioner or heat pump from the serial number?

Monday, December 16, 2019

You can determine the “nominal” size of your HVAC system by examining the model number on the data plate at the side of the condenser (outdoor unit). Just like the nominal size of lumber or an air conditioning filter, the exact cooling capacity may be a little more or less than the nominal rating, but it’s close. The model number on GE systems is stamped instead of printed and can be a little hard to read, but the number shown above is BTB718 A100A1.

For GE, you should look for the second and third of the three numbers in the center of the model number that are divisible by 6 or 12, which represent the nominal BTU of the system in thousands. A ton of air conditioning equals 12,000 BTU, and 18 divided by 12 equals 1.5, so the data plate above indicates the system is 1-1/2 tons.

Here’s a rundown of the range you will encounter: 18 = 1.5 tons, 24 = 2 tons, 30 - 2.5 tons, 36 = 3 tons, 42 = 3.5 tons, 48 = 4 tons, and 60 = 5 tons.

If you are unsure whether you have found the right two numbers, you can double-check it by looking for the “RLA” rating on the data plate. RLA is an acronym for Rated Load Amperage, and is what the maximum amperage should be when the condenser up and running. If you divide the RLA by 6 for older units and 5 or 6 for newer units, you should get a number that approximates (not exactly) the tonnage of the system. Make sure you use RLA and not LRA, Locked Rotor Amperage, which is the surge of amps necessary to overcome inertia and start the system. It averages around five times the RLA.

To find out the age of your GE system, go to our blog post How do I determine the age of a GE (General Electric) air conditioner or heat pump for the serial number? and, for other key specs, see these articles below:

How can I find out the SEER of my air conditioner?

How can I tell whether the condenser (outdoor unit) is an air conditioner or heat pump?

• • • • • • • • • • • • • • • • • • • • • • • • • • • • • • •

My air conditioner won't turn on. What's wrong?

How can I find out the size of my air conditioner?

Where is the air filter for my central air conditioner and furnace? I can’t find it?

Does an old air conditioner use more electricity as it ages?

What is wrong with an air conditioner when the air flow out of the vents is low?

Why has the thermostat screen gone blank?

Why does it take so long to cool a house when an air conditioner has been off for a while?

Why is my air conditioner not cooling enough?

What are the most common problems with wall/window air conditioners?

Visit our HEATING AND AIR CONDITIONING page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.

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