Cooling Degree Days
Cooling degree days (CDD) are a climate metric used to assess cooling energy demand in buildings and plan for HVAC efficiency and sustainability.
September 30, 2025
What are Cooling Degree Days?
Cooling degree days (CDD) are a climate metric used to estimate cooling demand in buildings. They are calculated by summing the difference between the daily average temperature and a base temperature (commonly 18°C or 65°F) for days above the threshold. Higher CDD values mean greater energy demand for air conditioning and cooling systems.
Why Cooling Degree Days Matter in Real Estate
Cooling degree days matter because they impact HVAC design, energy budgeting, and sustainability planning. Developers, engineers, and property managers use CDD data to estimate long-term operating costs, identify retrofit opportunities, and compare energy performance across properties or regions. Rising CDD values also highlight climate change implications for the built environment.
Example of Cooling Degree Days in Action
A property manager tracks CDD trends and finds that one multifamily building consistently consumes more cooling energy than expected. Benchmarking against CDD data reveals inefficiencies in insulation and HVAC systems, leading to a retrofit that reduces operating costs by 15%.
Key Takeaways
- Cooling degree days measure climate-related cooling demand.
- They are vital for HVAC design and retrofit planning.
- Higher CDD values signal greater energy consumption.
- Benchmarking against CDD improves efficiency strategies.
- Climate change increases the importance of monitoring CDDs.
Related Terms
- Energy Benchmarking
- HVAC Systems
- Green Building Certification
- Operating Costs
- Sustainability
6525 Mississauga Road and its surrounding context. (RBC Capital Markets & CBRE)
Property details for 6525 Mississauga Road. (RBC Capital Markets & CBRE)
National average resale-price growth and housing-starts growth, smoothed over three months. The comparison illustrates the cycle; it does not establish how much a price change causes construction to change.
Trailing 12-month starts in centres of 50,000 or more remove the usual monthly seasonality. Ownership combines the homeowner and condominium categories; rental is shown separately.
Six-month averages of provincial starts, expressed at annual rates. The smoothing reduces the influence of individual apartment projects.
The same August benchmark compared with two different starting points. Three-month changes are not annualized.
Average sale prices show the difference in purchase costs across markets. They do not measure affordability relative to local incomes or construction costs.
Newfoundland and Labrador remains above its pre-pandemic sales pattern, but August activity was below last year. Historical lines retain their original release vintages.
Average and median describe different aspects of the same month’s transactions. Both are affected by the mix of homes sold.
Category averages compare different homes and locations; the gaps are not estimates of the cost to upgrade an otherwise identical property.
The five categories shown account for 5,000 of the board’s 5,057 sales. The remaining 57 transactions were in other housing categories.
Monthly observations are not seasonally adjusted. Active listings count properties available at month-end; they are not construction inventory.
Average and median prices share one dollar axis. These unadjusted transaction measures do not control for changes in the homes sold.
TRREB’s 416/905 categories compare the apartments sold in each area. The difference does not isolate a location premium for equivalent units.
5680 Oak Street in Vancouver and its surrounding context. (MCMP Architects)
Ground-level renderings of the tower proposed for 5680 Oak Street in Vancouver. (MCMP Architects)