The higher the EER number, the more efficient the appliance. Degree days are neither degrees nor days, but rather a made-up term to measure the amount of variance in the weather. The base is 65 degrees Fahrenheit. Degree days are the sum of the daily temperature variances from the base of 65 degrees measured for an entire heating and cooling season. For example, a day with an average temperature or 72 degrees has 7 cooling degree days while a day with an average temperature of 25 degrees has forty heating degree days.
Degree days are useful in measuring temperature variances between various time periods.
In an average year, Detroit has 6,228 heating degree days, and 743 cooling degree days. Anchorage Alaska has 10,911 heating degree days and 0 cooling degree days. Honolulu has 0 heating degree days, and 4,221 cooling degree days. Most other cities are in between. Closest cities to Detroit are Chicago, Omaha, Hartford, and Cleveland.