Home
Back
Heating Degree Days Formula:
| From: | To: |
The Home Heating Index, measured in Heating Degree Days (HDD), quantifies the demand for energy needed to heat a building. It represents how much and for how long the outside air temperature was below a specified base temperature.
The calculator uses the Heating Degree Days formula:
Where:
Explanation: The calculation sums the daily differences between the base temperature and average daily temperature. Only positive differences are counted (when average temperature is below base temperature).
Details: HDD is crucial for energy companies to predict heating demand, for homeowners to estimate heating costs, and for researchers studying climate patterns and energy consumption trends.
Tips: Enter base temperature (typically 65°F) and average daily temperature in Fahrenheit. The calculator will compute the heating degree days for a single day. For cumulative HDD, sum daily calculations over your desired period.
Q1: What is the standard base temperature for HDD?
A: 65°F (18.3°C) is the most commonly used base temperature, as it represents the temperature below which buildings typically require heating.
Q2: How is HDD used in practice?
A: Utility companies use HDD to forecast energy demand, homeowners use it to compare heating costs across seasons, and energy auditors use it to assess building efficiency.
Q3: What's the difference between HDD and CDD?
A: HDD (Heating Degree Days) measures heating demand when temperatures are below the base, while CDD (Cooling Degree Days) measures cooling demand when temperatures are above the base.
Q4: Can HDD be calculated for different base temperatures?
A: Yes, different base temperatures can be used depending on the building type, insulation quality, and local climate conditions.
Q5: How accurate is HDD for energy estimation?
A: HDD provides a good estimate but doesn't account for factors like solar gain, wind chill, humidity, or building-specific characteristics.