Degree Day Information

Degree Day Information

  • Reflects how warm or cold it was during a specific period.
  • The larger the number, the colder the temperature was.
  • You usually use more heating fuel in colder weather because your furnace is working harder to maintain comfortable temperatures.
  • Degree day calculations are based on the assumption that a building does not require any heat if the outside temperature averages 65 degrees during a 24-hour period.

Calculate degree days:

  1. Add the highest temperature to the lowest temperature for the period.
  2. Divide the total by two.
  3. Subtract the result from 65.

Example:

If the day's high temperature was 30 degrees and the low was 10 degrees:

Degree Day Example

Use degree days to compare energy consumption for a given time period:

  • Calculating your energy use per degree day will reduce the weather impact on your comparison.
  • To find natural gas use per degree day, divide the number of therms used by the number of degree days for the same period.

Example therms for an example home:

  • 146 therms for the billing period in December 2001.
  • 239 therms for the billing period in December 2002.

Degree days for example billing period:

  • 724 degree days during the December 2001 billing period.
  • 1,222 degree days during the December 2002 billing period.

Natural gas use per degree day:

  • .20 in December 2001.
  • .195 in December 2002.

This home was using energy more efficiently in December 2002.