How do we adjust air conditioning energy for a hotter year?
Use cooling degree days. They add up how far each day's temperature was above a base, often 18 to 24 C. Plot monthly cooling kWh against degree days for a past year. The fitted line shows what a normal year would use, so a hot summer does not hide a real saving.
Steps
- Separate cooling kWh by sub-meter, or estimate it from summer and winter bills.
- Get monthly degree days for the nearest weather station.
- Fit kWh against degree days and report actual and normalised figures.
What to report
Report actual emissions in the inventory. Use the normalised figure only to explain performance, and label it.
What Senseible does here
Senseible reads fuel invoices and electricity bills and applies IPCC 2006 factors and the CEA grid factor (0.710 kg CO2 per kWh), so you can compare Scope 1 and 2 before and after a change from the documents themselves.
Sources: GHG Protocol Corporate Standard, International Energy Agency, Bureau of Energy Efficiency
Last reviewed 2026-10-23.