1. What is the Heat Requirement Equation?

The heat requirement equation calculates the amount of heat needed to maintain a building at a comfortable temperature. It considers heat loss through the building envelope (UA × ΔT) and through ventilation.

2. How Does the Calculator Work?

The calculator uses the heat requirement equation:

Where:

• \( UA \) — Overall heat transfer coefficient (W/°C)
• \( \Delta T \) — Temperature difference between inside and outside (°C)
• \( Ventilation\ Loss \) — Heat loss through air exchange (W)

Explanation: The equation accounts for both conductive heat loss through walls/windows and convective heat loss through air changes.

3. Importance of Heat Calculation

Details: Accurate heat requirement calculation is crucial for proper HVAC system sizing, energy efficiency, and maintaining comfortable indoor conditions.

4. Using the Calculator

Tips: Enter UA value in W/°C, temperature difference in °C, and ventilation loss in W. All values must be valid (UA > 0).

5. Frequently Asked Questions (FAQ)

Q1: How do I determine the UA value for my building?
A: UA is calculated by summing the U-values of all building elements multiplied by their respective areas.

Q2: What's a typical temperature difference (ΔT) to use?
A: This depends on your location and desired indoor temperature. A common ΔT is the difference between 20°C indoor and the coldest outdoor temperature expected.

Q3: How is ventilation loss calculated?
A: Ventilation loss = 0.33 × air changes per hour × volume × ΔT (in °C)

Q4: Should I include internal heat gains?
A: This calculator provides gross heat requirements. For net requirements, subtract internal gains from occupants, appliances, etc.

Q5: What about heat loss through the ground?
A: Ground-coupled heat loss requires different calculation methods not included in this simplified equation.