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Sizing a Central Air Conditioner for Your Home

Central air conditioner label
used to determine sizing

Central air conditioner label used to determine sizing for your replacement central air conditioner

Sizing an air conditioner is a fairly simple process. Some HVAC service contractor’s use what is known as a manual J load calculation to determine the air conditioner size that a home requires.  While this is a good way to size an air cooling system for a house under construction where all the insulation values and the tightness of the home are known, it can be fairly inaccurate when cooling existing structures. The best way to determine the correct air conditioning system size for your home is to access how well the old system worked. If your old system did the job in cooling, your new system will do the same job more efficiently.

If you are unsure of your central air system’s size, simply look at the nameplate on the outdoor AC unit.  Almost all air conditioner manufactures put the Btu rating in the model number.  One ton of cooling is equal to 12,000 Btu’s.  Most units start at 2 ton, or 24,000 btu’s and increase in half ton increments, skipping 4-1/2 ton.

Here is a central air conditioner label model number example:

central air conditioner label model number for sizing your replacement central air conditioner

4SCU13LE130P-1 — 30 is the answer.

This is a 2-1/2 ton central air conditioning system. Sometimes you have to do a little detective work to find the Btu number because there is no set location within the AC model number and it varies by manufacturer.  If you can’t figure it out, give us a call or contact us with the number and we will be glad provide you with the system size.

If your old system didn’t do a satisfactory job in cooling your home, we will be happy to send out a technician, at no charge, to review your particular application and come up with a solution.