Annual Cooling Cost Calculator
Instructions:
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Review the methodology to make sure it aligns with your project's requirements.
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Input the unit's capacity.
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Select if the SEER of the unit is just SEER or SEER2.
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If it's SEER, input the value.
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If it is SEER2, please specify the unit type and input the value.
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Input the cooling load hours if you know them. If not, you can select a city close to the location of your building for an approximation.
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The default electric rate is $0.12, but you can change it for a more accurate result.
Capacity (Btu/h) / SEER × cooling degree days / 1000 × electric rate = annual cost of operation. Cooling degree days are base 65 °F, from the ASHRAE handbook (2017).
A SEER2 rating is converted to SEER first, dividing by the ratio for the equipment type: 0.96 single package, 0.95 single split, 1.00 small duct high velocity, 0.99 space constrained. Leaving the equipment type unselected uses the rating as entered.
Choosing a city fills in its cooling degree days and overrides the box below it. Leave the city on "Select a city" to use a figure of your own.
Methodology, Equation, Examples:
The Annual cooling cost calculator estimates the cost of running an AC unit over the course of a year. The formula that we use to calculate this is as follows.
Capacity (Btuh)/SEER X Cooling Degree Days/1000 X Elec. Rate = Annual Cost of Operation
For the efficiency value in this equation, you can input SEER or SEER2, which will automatically be converted into the correct form. To see how this conversion works check out our EER SEER2 COP HSPF2 kw/Ton Converter. We are pulling the Cooling Degree Days from the ASHRAE handbook. For the specific cooling degree days, we are looking at the base 65°F CDD.
Example
A 38,000 Btuh system with a SEER of 11.00 located in Miami Florida, with an electrical rate of 12 cents per kwh (kilowatt hour). Plugging this in we get...
38,000 Btuh / 11 X 4259 CDD /1000 X 0.12 cents = $ 1765.55 per year
Now, using the calculator, we get the same result.
Relevant citations:
Cooling Degree Days from ASHRAE (2017)
The formula for the Annual Cost of Operation
Further information about cooling degree days can be found here and here