1. What is a Radiator BTU Calculator?

Definition: This calculator estimates the heat output required from a radiator based on room temperature difference, radiator specifications, and surface area.

Purpose: It helps homeowners and heating professionals determine the appropriate radiator size for a room according to UK standards (B&Q).

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Heat output (BTU/h or Watts)
• \( \Delta T \) — 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 coefficient and surface area gives the heat output.

3. Importance of Correct BTU Calculation

Details: Proper heat output estimation ensures comfortable room temperatures, energy efficiency, and correct radiator sizing.

4. Using the Calculator

Tips: Enter the temperature difference (typically 50°C for UK systems), heat transfer coefficient (default 11 W/m²·K for standard radiators), and radiator surface area.

5. Frequently Asked Questions (FAQ)

Q1: What temperature difference should I use?
A: For UK central heating systems, use 50°C (flow at 70°C, return at 50°C, room at 20°C).

Q2: What's a typical K value for radiators?
A: Standard panel radiators are about 11 W/m²·K, while convector radiators might be higher.

Q3: How do I find my radiator's surface area?
A: Check manufacturer specifications or measure length × height × number of panels.

Q4: Should I add extra capacity?
A: Add 10-20% for rooms with large windows, external walls, or high ceilings.

Q5: What's the difference between Watts and BTU?
A: 1 Watt = 3.412 BTU/h. UK radiators are often rated in both units.