AC Sizing: What To Know About BTUs And Tons

When you need to buy a new air conditioner for your home, the main question you may have is how powerful of an air conditioner you need to buy. For window units, it is as simple as figuring out the total square footage of a room, which translates to the unit's BTUs. However, central air conditioning can be complicated because the strength of the unit is measured in tons. Here is what you need to know about these terms so you buy the right air conditioner.

Understanding BTUs

A BTU is essentially how much energy it will take to increase the temperature of 1 lb. of water by 1°F. You can conclude from this that the higher number of BTUs an air conditioner delivers, the more powerful it is going to be. Air conditioners with 4,000 BTUs of cooling power are going to cool down a larger square footage compared to weaker units, or cool down smaller spaces much faster than weaker units. You'll often find that window units are measured just in BTUs because of their relationship to square footage of a single room.

Understanding Tons

Central air conditioning systems still use BTUs, but use another unit of measurement on top of that. A common term you'll hear when describing a central air conditioning is tons, with 12,000 BTUs equaling 1 ton. The reason the measurement is called a ton is because that is how much energy is required to melt literally 1 ton of solid ice within a single day.

HVAC contractors find it easier to use the ton measurement to figure out what size air conditioner is necessary to cool off an entire home, because it is dealing with a much larger square footage than a single room. Instead of saying you need a 48,000 BTU air conditioner to cool down a house, it's easier to say you need a 4 ton air conditioner.

Selecting the Right Size AC Unit

The problem with using air conditioning is that the unit needs to be sized correctly for your home's square footage. Selecting a unit that's too powerful can cause problems where the unit wastes electricity or cycles on and off too quickly. A unit that's too weak can run constantly and not be able to keep up with cooling the entire home.

An HVAC contractor, like those at Eastern Shore Heating & Air, Inc, can take the proper measurements of your home to determine how large of an AC unit you need, which is usually about 1 ton for 100 sq. ft. of finished living space in your house. This is the best way to ensure you are installing a unit that is the proper size.