1. What is a B and Q BTU Calculator?

Definition: This calculator estimates radiator heat output based on temperature difference, heat transfer coefficient, and surface area according to UK standards.

Purpose: It helps homeowners and professionals determine appropriate radiator sizing for heating requirements.

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 heat transfer coefficient and surface area gives the heat output in Watts, which is then converted to BTU/h.

3. Importance of Heat Output Calculation

Details: Proper heat output estimation ensures efficient room heating, energy savings, and correct radiator selection.

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 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: What K value should I use?
A: Standard radiators use ~11 W/m²·K. Check manufacturer specs for specific radiators.

Q3: How do I find radiator surface area?
A: Measure height × width × number of panels × manufacturer's conversion factor.

Q4: Why show both Watts and BTU?
A: Watts are standard in UK, BTU is common for comparison with older systems.

Q5: Does this include heat loss factors?
A: No, consider adding 10-20% for rooms with high heat loss (e.g., large windows).