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SIZING GUIDE
calculate your system size
MAKE THE RIGHT CHOICE
Hey! Use the sizing calculator below to calculate your system size. Follow these easy steps:
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Select the region you live in according to the color keyed map below.
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Select the system type needed for your home.
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Select the optional heating type.
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Enter the approximate square feet of the area in your home that you need to heat/cool.
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Click the "Calculate System Size" button.
AIR CONDITIONING SQUARE FOOTAGE RANGE BY CLIMATE ZONE
The sizing chart below is useful to help you determine your approximate central air conditioner size requirements.
PROPER SYSTEM SIZING
Backed with science, the Residential Load Calculation is a method used to calculate and select the right central air conditioner for you.
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Another way to size air conditioners is to determine the system size currently in place. Manufacturers normally don't list the size of the air conditioner unit. However, the system capacity is typically coded into the model number of the outdoor unit.
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For example, model GSX140241K is a 2 ton unit. Why? There are 12,000 Btu's per ton. The number 24 in the model number indicates the unit is 24,000 Btu's, divided by 12,000 Btu's per ton, equals 2 tons.
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24,000 Btu's/12,000 Btu's per ton = 2 tons
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Use the following conversion information to determine your existing system size. (Use the system model number NOT the serial number)
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18 = 1.5 tons
24 = 2 tons
30 = 2.5 tons
36 = 3 tons
42 = 3.5 tons
48 = 4 tons
60 = 5 tons
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A Word of Advice: be careful not to make the mistake of buying an A/C that's too large! If the system you install is too large for the space, it will short cycle. In other words, the compressor will not run long enough to dehumidify the space and will limit your comfort. Additionally, the system will cycle on and off more often​, increasing operating costs and reducing the system life. Proper air conditioner sizing is critical to optimize performance.
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Still have questions or concerns? Please e-mail us or call us toll free number at
HEATING SQUARE FOOTAGE BY CLIMATE ZONE
HEATING GUIDE
How to use the heating guide portion of this selection guide.
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To begin, either use the lower of the two numbers if you know your home to be well insulated or use the higher number if your home is older and poorly insulated. (Hint: Select the larger of the two numbers if you're completely unsure of your home's insulation).
Then, multiply the number above by your home's total heated square footage. At this point, you should arrive at your approximate heating capacity requirement.
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Example reference: If your home is in the yellow zone, your home is adequately insulated, and you've got 2000 heated square feet, the equation will look like this:
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2000 square feet
X 40 heating factor (from the chart above)
80,000 Btu actual output
Next, if you need to calculate the output you need on a gas furnace, simply multiply its efficiency by its listed input rating for the BTU output of heat.
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Example reference: If a furnace is listed with an input rating of 100,000 BTU's and an efficiency rating of 80%, it would produce:
100,000 Btu input
X .80 efficiency
80,000 Btu actual output
If the same 100,000 BTU furnace has an efficiency rating of 93% it will produce:
100,000 Btu input
X .93 efficiency
93,000 Btu actual output
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In the example above, using an 80% efficient furnace, the 2000 square foot home above would require a 100,000 BTU input furnace which will produce the necessary 80,000 BTU's output of heat.
VARIABLES
Variables such as your insulation, type and number of windows, number of stories, construction type, etc. should be considered. Variables will affect the required BTU's per square for both heating and cooling. A general rule of thumb is that if your home is well insulated with newer style windows, you can select the smaller size system that falls within your total square footage.
If your home is two story, it will place less of a load on the system in the downstairs area as the second floor acts as additional insulation. If your home is not well insulated, has older style windows, and/or a high number of windows, select the larger system which falls within your square footage range. The less insulated and more windows within the environment, the more likely you will experience greater air and heat loss.
DUCT WORK SIZING
Duct work sizing is critical when upgrading or changing your system. Here's a simple guide to size your duct work. This guide is only to be used as an estimate, and we would highly recommend a technician to check your duct work and ensure that the proper duct work size is used. Click here to see the duct work sizing chart.
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