SEER Savings Calculator

A seasonal efficiency rating is BTU of cooling delivered per watt-hour of electricity, so capacity, running hours and your electricity rate are all it takes to price a season of cooling. Enter the system size, the cooling hours for your area and the rate off your own bill, and the page gives the annual cost at one rating, the saving between two ratings and the simple payback on the extra cost of the higher one. SEER2 and SEER come from different tests rather than being the same scale, so there is a converter here and a warning on every result against comparing one against the other. The cooling hours figure is the weakest number on the form and can easily be a third out, which moves every dollar amount with it.

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Two ratings, one load, and the price difference between the units.

Nominal capacity. One ton is 12,000 BTU per hour, so a 3 ton system is 36,000.
Equivalent full-load cooling hours for your area: roughly 400 to 800 in the northern states, 1,000 to 1,600 across the middle, and 1,800 to 2,800 in the hottest and most humid parts of the south and southwest. Your utility or a local contractor will have a better figure than any national average.
Take the total of a summer bill and divide it by the kWh on the same bill, so delivery charges and taxes are in the figure rather than just the energy rate.
Whatever is on the existing unit. Systems from before 2006 are often 8 to 10.
The difference in installed price between the two units, not the price of the whole job. That difference is what the saving has to pay back.
Fifteen years is a common working life for a split system.
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What a single system costs to run for a season at your rate.

Nominal capacity. One ton is 12,000 BTU per hour, so a 3 ton system is 36,000.
Equivalent full-load cooling hours for your area: roughly 400 to 800 in the northern states, 1,000 to 1,600 across the middle, and 1,800 to 2,800 in the hottest and most humid parts of the south and southwest. Your utility or a local contractor will have a better figure than any national average.
Take the total of a summer bill and divide it by the kWh on the same bill, so delivery charges and taxes are in the figure rather than just the energy rate.
Only used to spread the annual figure across the months you actually run it.
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The two ratings come from different tests. This puts an old figure on the new scale, or the reverse.

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