Cooling Degree Day Calculator

Cooling Degree Day (CDD) Formula:

\[ CDD = \max\left(\frac{T_{max} + T_{min}}{2} - 65, 0\right) \]

Cooling Degree Days (CDD):

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1. What is Cooling Degree Day (CDD)?

Cooling Degree Day (CDD) is a measurement designed to quantify the demand for energy needed to cool buildings. It is based on the principle that energy consumption for cooling increases as the outdoor temperature rises above a certain base temperature (typically 65°F).

2. How Does the Calculator Work?

The calculator uses the CDD formula:

\[ CDD = \max\left(\frac{T_{max} + T_{min}}{2} - 65, 0\right) \]

Where:

\( T_{max} \) — Maximum daily temperature (°F)
\( T_{min} \) — Minimum daily temperature (°F)
65 — Base temperature for cooling (°F)

Explanation: The calculation takes the average of daily high and low temperatures, subtracts the base temperature (65°F), and sets negative results to zero.

3. Importance of CDD Calculation

Details: CDD calculations are essential for energy management, utility planning, and predicting cooling energy requirements. They help energy providers forecast demand and assist building managers in optimizing HVAC system performance.

4. Using the Calculator

Tips: Enter maximum and minimum temperatures in Fahrenheit. The calculator will compute the cooling degree days based on the standard 65°F base temperature.

5. Frequently Asked Questions (FAQ)

Q1: Why is 65°F used as the base temperature?
A: 65°F is a standard baseline where buildings typically require neither heating nor cooling. Temperatures above this level indicate cooling demand.

Q2: How are CDD values typically used?
A: CDD values are used by energy companies to predict electricity demand, by researchers studying climate patterns, and by building managers to optimize energy efficiency.

Q3: What's the difference between CDD and HDD?
A: CDD measures cooling demand (temperatures above base), while Heating Degree Days (HDD) measure heating demand (temperatures below base).

Q4: Can CDD be calculated in Celsius?
A: Yes, but the base temperature would be different (typically 18.3°C instead of 65°F). This calculator uses Fahrenheit for consistency with common US energy calculations.

Q5: How accurate are CDD predictions for energy use?
A: While CDD provides a good general indicator, actual energy consumption can be affected by factors like building insulation, humidity levels, and occupant behavior.