Standard heating and cooling degree days for the UK

The following table provides a fixed basis for weather-correcting energy consumption figures. It is compatible with the standard annual total heating degree days cited in government publications which deal with normalised performance indicators (NPIs), but extends the scope to include

• cooling loads
• alternative base temperatures
• incomplete years' data

This table may be freely reproduced provided that the source is acknowledged

|       |          Heating           |          Cooling          |
| Month |  18.5'C   15.5'C   10.0'C  |  15.5'C   5.0'C  -20.0'C  |
|       |                            |                           |
|  Jan  |    488      395      226   |     0       17      705   |
|  Feb  |    426      342      189   |     0       23      652   |
|  Mar  |    390      297      134   |     0       64      803   |
|  Apr  |    319      233       96   |     5      114      837   |
|  May  |    235      151       39   |    14      192      963   |
|  Jun  |    148       77        9   |    26      265     1015   |
|  Jul  |     88       42        4   |    96      380     1155   |
|  Aug  |    100       44        5   |    57      338     1113   |
|  Sep  |    162       83       10   |    14      245      995   |
|  Oct  |    268      177       48   |     1      158      925   |
|  Nov  |    359      275      124   |     0       53      719   |
|  Dec  |    439      346      176   |     0       29      755   |
|       |                            |                           | 
| Total |  3,422    2,462    1,060   |   213    1,878   10,637   |

The procedure is as follows:

1. Decide whether the load is predominantly heating or cooling related, and then select the most appropriate base temperature (the base temperature is the outside air temperature at which weather-related energy demand would be nil). This determines which column of figures to use.

2. For the period under study, establish the weather-related energy consumption and the actual degree days recorded in the region in question. Use heating or cooling degree days as determined in step 1, to the chosen base temperature.

3. Divide the weather-related energy consumption by the actual degree days and multiply the result by the standard degree days from the table above. This gives the weather-corrected energy consumption.

4. Remember to add back the non-weather-related consumption (deducted in step 2) to the result from step 3.

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