1. What is an Existing Radiator BTU Calculator?

Definition: This calculator estimates the heat output (in BTUs) of an existing radiator based on its size, temperature difference, and heat transfer characteristics.

Purpose: It helps HVAC professionals and homeowners determine the heating capacity of radiators for system evaluation and balancing.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Heat output (BTU/hour)
• \( \Delta T \) — Temperature difference between radiator and room (°F)
• \( K \) — Heat transfer coefficient (BTU/h·ft²·°F)
• \( A \) — Radiator surface area (ft²)

Explanation: The temperature difference drives heat transfer, while the K factor represents the radiator's efficiency, and area determines total heat exchange capacity.

3. Importance of Radiator BTU Calculation

Details: Accurate BTU calculation ensures proper heating system performance, energy efficiency, and room comfort levels.

4. Using the Calculator

Tips: Enter the temperature difference (typically 50-70°F), K value (default 1.5 for cast iron), and radiator surface area. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: How do I measure temperature difference?
A: Subtract room temperature from average radiator surface temperature.

Q2: What K value should I use?
A: Typical values: 1.5 for cast iron, 2.0 for steel panel, 1.2 for old cast iron.

Q3: How do I find radiator surface area?
A: Measure length × height × number of sections × manufacturer's section area factor.

Q4: Does this work for baseboard heaters?
A: Yes, but use appropriate K values (typically 2.5-3.0 for finned-tube baseboard).

Q5: How accurate is this calculation?
A: It provides a good estimate but actual output may vary based on water temperature, flow rate, and radiator condition.