1. What is a Domestic Heat Loss Calculator?

Definition: This calculator estimates the heat loss from a building based on U-values, surface areas, temperature differences, and air infiltration.

Purpose: It helps homeowners and builders determine heating requirements and improve energy efficiency in UK homes.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Total heat loss (Watts)
• \( U \) — U-value of building element (W/m²K)
• \( A \) — Area of building element (m²)
• \( \Delta T \) — Temperature difference between inside and outside (Kelvin)
• Infiltration — Heat loss through air leaks (Watts)

Explanation: The calculator sums heat loss through all building elements plus additional losses from air infiltration.

3. Importance of Heat Loss Calculation

Details: Accurate heat loss calculations ensure proper heating system sizing, improve energy efficiency, and help meet UK building regulations.

4. Using the Calculator

Tips:

• U-values: Walls ~0.3, Windows ~1.6, Roof ~0.15 W/m²K (UK standards)
• ΔT: Typically 21K (indoor 21°C vs outdoor 0°C)
• Infiltration: Add if known (or use 0 for just fabric loss)

5. Frequently Asked Questions (FAQ)

Q1: What is a typical U-value for UK homes?
A: Modern UK homes aim for walls ~0.3 W/m²K, windows ~1.4-1.6 W/m²K, roofs ~0.15 W/m²K.

Q2: How do I estimate infiltration losses?
A: For a typical UK home, infiltration might add 10-20% to fabric losses. Use 0 if unknown.

Q3: Why is ΔT typically 21K?
A: This represents heating to 21°C when it's 0°C outside - the standard design condition for UK heating systems.

Q4: How do I calculate heat loss for multiple elements?
A: Calculate each element separately and sum the results, or use our Whole House Heat Loss Calculator.

Q5: Does this account for thermal bridges?
A: No, for precise calculations consider adding 5-15% to account for thermal bridging in UK homes.