What are Degree Days and how are these used as part of an energy management plan?
Heating degree day (HDD) and cooling degree day (CDD) are quantitative indices designed to reflect the demand for energy needed to heat or cool a building. These indices are derived from daily temperature readings, and the heating (or cooling) requirements for a given building at a specific location are considered to be directly proportional to the number of heating degree days at that location. In the UK, Heating degree days use a base temperature of 15.5 degC. When managing energy, degree days allow you to assess heating (or cooling) energy consumption. This is done by plotting and scatter graphs with monthly (or weekly) gas consumption on the X-axis against monthly (or weekly) degree day totals on the Y-axis. This should produce a diagonal trend line. To assess the building’s energy consumption it can be said that any month with poor (high) energy consumption will appear above the line and months with better (low) energy consumption below. By continually plotting this graph an energ
