1. What is a Heat Pump Heat Loss Calculator (UK)?

Definition: This calculator estimates the heat loss of a building according to UK standards, helping to properly size heat pump systems.

Purpose: It helps homeowners, architects, and heating engineers determine the heating requirements for UK buildings.

2. How Does the Calculator Work?

The calculator uses the UK standard formula:

Where:

• \( Q \) — Total heat loss (Watts)
• \( U \) — U-value of building elements (W/m²K)
• \( A \) — Surface area of building elements (m²)
• \( \Delta T \) — Temperature difference between inside and outside (Kelvin)
• \( \text{Ventilation} \) — Heat loss through air changes (Watts)

Explanation: The calculator combines fabric heat loss (U×A×ΔT) with ventilation heat loss to give total building heat loss.

3. Importance of Heat Loss Calculation

Details: Accurate heat loss calculations ensure heat pumps are correctly sized for efficiency and comfort, preventing under- or over-sizing.

4. Using the Calculator

Tips:

• U-value: Default 0.18 W/m²K (UK building regs for walls)
• ΔT: Default 21K (difference between 21°C inside and 0°C outside)
• Ventilation: Default 150W for average UK home

5. Frequently Asked Questions (FAQ)

Q1: What's a typical U-value for UK homes?
A: For walls: 0.18-0.30 W/m²K (new builds to older homes). Windows: 1.2-2.8 W/m²K.

Q2: How do I calculate total surface area?
A: Measure external walls, roof, floor, and windows separately, then sum all areas.

Q3: What temperature difference should I use?
A: Use your desired indoor temperature minus the design outdoor temperature (-3°C to -1°C for most UK locations).

Q4: How is ventilation loss calculated?
A: 0.33 × air changes per hour × volume × ΔT, but we've simplified with typical values.

Q5: Does this include hot water requirements?
A: No, this calculates space heating only. Add 10-15% for hot water in domestic systems.