1. What is a Whole House Heat Loss Calculator?

Definition: This calculator estimates the total heat loss of a building according to UK standards, considering fabric loss (U-values) and ventilation losses.

Purpose: It helps homeowners, architects, and builders determine heating requirements and improve energy efficiency.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

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

Explanation: The calculator sums heat loss through all building elements plus any additional ventilation losses.

3. Importance of Heat Loss Calculation

Details: Accurate heat loss calculations are essential for proper heating system sizing, energy efficiency improvements, and compliance with UK building regulations.

4. Using the Calculator

Tips: Enter average U-value (default 2.5 W/m²K for older UK homes), total surface area, temperature difference (default 21K), and any ventilation losses.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical U-value for UK homes?
A: Older homes: 2.5 W/m²K, New builds: must meet current Building Regulations (around 0.3 W/m²K for walls).

Q2: How do I find my home's surface area?
A: Calculate external wall, roof, and floor areas from plans or measurements (length × height for walls).

Q3: What temperature difference should I use?
A: Standard is 21K (21°C inside minus 0°C outside), but adjust for your location and desired indoor temperature.

Q4: How do I estimate ventilation losses?
A: Use 0 for modern airtight homes, or calculate using: 0.33 × air changes per hour × volume × ΔT.

Q5: Does this include heat loss through thermal bridges?
A: No, for precise calculations you should add 10-15% to account for thermal bridging in UK homes.