1. What is a Radiator BTU Size Calculator?

Definition: This calculator estimates the heat output of radiators based on UK standards using temperature difference, heat transfer coefficient, and surface area.

Purpose: Helps homeowners and heating engineers properly size radiators for efficient room heating.

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 formula calculates how much heat a radiator can emit based on its physical properties and operating conditions.

3. Importance of Proper Radiator Sizing

Details: Correctly sized radiators ensure comfortable room temperatures, energy efficiency, and prevent under/over heating.

4. Using the Calculator

Tips:

• Typical ΔT for UK systems: 50°C (flow 75°C, return 65°C, room 20°C)
• Standard K value for panel radiators: ~11 W/m²·K
• Measure radiator height × width × number of panels for area

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between Watts and BTU?
A: Both measure heat output. 1 Watt ≈ 3.412 BTU/h. UK radiators are typically rated in Watts.

Q2: How do I find my radiator's surface area?
A: Measure height × width (in meters), multiply by number of panels (single=1, double=2).

Q3: What if my radiator has fins?
A: Finned radiators have higher K values - consult manufacturer specifications.

Q4: How does room size affect radiator sizing?
A: Larger rooms need greater heat output. This calculator provides the radiator's capacity - you'll need enough capacity for your room size.

Q5: What about heat loss factors?
A: This calculates maximum output. Actual requirements depend on insulation, windows, and other heat loss factors.