Why we need to adjust utility calculations for weather
We know that weather can change a lot from year to year. However, did you know that since the year 2000, the influence of temperature on building energy use from one year to the next has at times varied by more than 20%?
The chart below, updated to include 2020 data, shows the Heating Degree Days (HDDs) over the last 30 years for Vancouver. HDDs are a key figure used for predicting building energy use and are directly calculated from the weather and a “balance point”, in this case 15 degrees Celsius. HDDs are a measure of how much heating energy is required over a period. The balance point is the temperature below which a building requires heating.
Remember the lack of snow on Cypress at the 2010 Olympics? You can see that the average HDDs that year was 9% less than the 30-year average, as reflected in the chart below.
The most remarkable thing about this chart is how much it varies year to year. This variation is why PUMA uses weather data and built-in algorithms for utility use calculations.