1. What is a Stelrad Heat Loss Calculator?

Definition: This calculator estimates heat loss from a building using the standard Stelrad formula, accounting for fabric and ventilation losses.

Purpose: It helps heating engineers and homeowners determine the heating requirements for a space to maintain comfort levels.

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)
• Ventilation — Additional heat loss from air changes (Watts)

Explanation: The calculator sums the fabric heat loss (U × A × ΔT) for all elements and adds any ventilation losses.

3. Importance of Heat Loss Calculation

Details: Accurate heat loss calculations ensure properly sized heating systems, energy efficiency, and comfortable indoor environments.

4. Using the Calculator

Tips: Enter the U-value (thermal transmittance), surface area, temperature difference (default 21K), and any ventilation losses. All values must be ≥ 0.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical U-value for UK homes?
A: Modern walls ~0.3 W/m²K, roofs ~0.15 W/m²K, single glazing ~5.0 W/m²K, double glazing ~1.4 W/m²K.

Q2: Why is ΔT typically 21K?
A: This assumes an internal temperature of 21°C and external of 0°C, common for UK heating design.

Q3: How do I calculate ventilation losses?
A: Ventilation loss = 0.33 × air changes per hour × volume × ΔT (or use specialist tools).

Q4: Should I calculate for each building element separately?
A: For whole-house calculations, sum (U×A) for all elements before multiplying by ΔT.

Q5: Does this include heat gains from occupants/appliances?
A: No, this calculates gross heat loss. Net heating requirement would subtract any heat gains.