1. What is a Radiator BTU Calculator?

Definition: This calculator estimates the heat output of a radiator based on temperature difference, heat transfer coefficient, and surface area.

Purpose: It helps heating engineers and homeowners determine the appropriate radiator size for a room according to UK standards.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Heat output (Watts or BTU/h)
• \( \Delta T \) — Temperature difference between radiator and room (°C)
• \( K \) — Heat transfer coefficient (W/m²·K)
• \( A \) — Radiator surface area (m²)

Explanation: The temperature difference multiplied by the radiator's heat transfer properties and size determines its heating capacity.

3. Importance of Radiator Sizing

Details: Proper radiator sizing ensures efficient heating, energy savings, and comfortable room temperatures.

4. Using the Calculator

Tips: Enter the temperature difference (typically 50°C for UK systems), heat transfer coefficient (default 11.0 W/m²·K for standard radiators), and surface area. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical ΔT value for UK systems?
A: Most UK heating systems use ΔT 50°C (flow 75°C, return 65°C, room 20°C).

Q2: How do I find my radiator's K value?
A: Check manufacturer specifications - typically 11.0 W/m²·K for standard panel radiators.

Q3: What's the difference between Watts and BTU?
A: 1 Watt ≈ 3.412 BTU/h. BTU (British Thermal Units) is commonly used for radiator sizing in the UK.

Q4: How do I measure radiator surface area?
A: For panel radiators: height × width × number of panels × front/rear factor (typically 1.8 for double panel radiators).

Q5: Should I add extra capacity?
A: Yes, add 10-20% for rooms with high heat loss (large windows, poor insulation, north-facing).