As I fine tune our VAV HVAC system (506,000 sq.ft. facility), we'd like to determine the effectiveness of our adjustments over time. As we both heat and cool portions of the building at the same time (electric VAV reheat), we need to apply degree days to the analysis. How is that done? Sometimes we're in heating degree days - sometimes cooling degree days. I'm guessing sometimes we're in both heating and cooling. I have access to total monthly KWHr & Therms of gas used.