OptiMiser recently integrated the latest database of 30-year weather normals from NOAA’s National Climatic Data Center. This data set covers the three decades from 1980 to 2010, replacing weather from the 1970s with data from the 2000s.
The 2000s reflected recent warming trends and averaged 1.5 degrees warmer than the 1970s, increasing overall 30-year averages by about 0.5 degrees. Auditors should be aware that if warming trends continue, estimates based on 30-year averages are still likely to under-predict future cooling loads and over-predict future heating loads on average.
Increased variability from climate change will likely mean that year-by-year and region-by-region differences between actual yearly loads and those predicted by 30-year normals become increasingly variable.