Degree Days: How They Figure In Energy-Use Calculations - Glasco Heating & Air Conditioning skip to Main Content

Degree days offer a means of calculating the amount of heating and cooling required by your home on a given day, month or year. This information can then be used to make comparisons to the heating and cooling averages of times past and better predict energy consumption in the future. How does it work?

Degree days are determined by comparing the average temperature of the day to a standard, 65-degree baseline. There are two ways of making this calculation:

  • During the summer, cooling degree days are calculated by taking the day’s average temperature and subtracting the 65-degree baseline. Thus, if temperatures ranged from 65 to 85 degrees on that day, the average temperature would be 75. To determine the cooling degree days you would simply subtract the 65-degree baseline from 75 to get a total of 10.
  • During the winter, you instead subtract the day’s average temperature from the 65-degree baseline. Thus, on a day where temperature ranged from 20 to 30 degrees, you would subtract the average 25-degree temperature from the 65-degree baseline for a total of 40 heating degree days.

To make comparisons to the heating and cooling averages of the past, you would simply add up the total degree days for the time period you wish to compare, be it a seven-day period or an entire season. Just remember to plug a zero in for days where the average temperature remained at 65. To find past information for comparison, consult the records of the National Weather Service.

Aside from energy consumption calculations, degree days are often used in other aspects of home comfort and energy-efficiency. For example, degree days are used to calculate the appropriate placement of vapor barriers in Connecticut basements, crawlspaces and attics. This makes them a major factor in household moisture control.

If you’d like more information on how degree days can help you improve the energy-efficiency of your household, contact one of our NATE-certified technicians. For expert consultation, contact Glasco Heating & Air Conditioning today. Our fleet covers the whole state of Connecticut.

Our goal is to help educate our customers about energy and home comfort issues (specific to HVAC systems).

Glasco Heating & Air Conditioning services South Windsor, Connecticut and the surrounding areas. To get started, check out our website.