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cooling degree day

The cooling degree day is unit used to relate the day's temperature to the energy demands of air conditioning. Cooling degree days are calculated by subtracting 65F (18C ) from a day's average temperature. For example, if the day's high is 90F and the day's low is 70F, the day's average is 80F. Eighty minus 65 is 15 cooling degree days.

Cooling degree days can be used to compare the current summer to past summers. Hence, by studying degree day patterns in your area, you can evaluate the increases or decreases in your heating or air-conditioning bills from year to year.

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