Analysis of cooling and heating degree days in the United States from 2015 to 2024

A sizable portion of the electricity consumed in buildings is due to the thermal load associated with the location of these buildings. Specific environmental characteristics can be translated into factors that allow researchers to understand the correlation between temperature changes and the energy necessary to heat and cool buildings. Heating Degree Days (HDD) and Cooling Degree Days (CDD) are parameters used to evaluate temperature changes depending on location. This study uses publicly available data to analyze the percentage change in HDD and CDD at 1,389 locations across the United States and finds sizable trends in both have occurred over the last 10 years. Importantly, there is no attempt here to attribute causes to these trends but rather report them. At each location, both HDD and CDD are plotted vs. year, and fit to a linear curve. The percentage change for each location is tabulated, and averages taken. Remarkably, the results show an increase in both CDD and HDD indices of 35.45% and 8.42% respectively, meaning on-average it got substantially hotter in summer, and colder in winter. The ultimate goal is to understand how the changes can be translated into the electricity usage pattern for cooling and heating across the country and affect electrical grid requirements going forward.