Analysis of errors in degree days for building energy analysis using Meteorolgical Office weather station data.

Heating degree days are widely used in building energy management for weather normalization of energy use. Degree days are normally calculated at Meteorological Office weather stations sited some distance from the building of interest and this can introduce errors between the degree days used in the calculations and the actual degree days at the building. This paper analyses the major sources of errors in the degree days derived from a newly available data set of Met. Office stations supplied by the British Atmospheric Data Survey (BADC) and compares these errors against those from other available data sets. The BADC data set consists of hourly temperatures for 242 weather stations in the UK from January 2001 until November 2007 and has been converted to monthly degree days for the analysis. The errors have been analysed in terms of measurement and recording errors, errors due to altitude and errors due to spatial separation between weather station and building. The largest error is due to spatial separation between building and weather station. It is therefore important to use data sets with high numbers of weather stations.