Heating Degree-Day Energy Estimate
Degree-days summarise how cold a season is relative to a base temperature.
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Use degree-day data from Environment Canada or NOAA for your location.
Formula
- Energy = UA × 24 × HDD ÷ efficiency
Example calculation
UA 500 BTU/h·°F, 7,000 °F·days, 95% → 88.4 MMBTU.
Practical HVAC use
Rough annual fuel cost comparisons.
Common mistakes
- Mixing °C and °F degree-days (°F-days = °C-days × 1.8).
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