1. What is a BTU Calculator for Radiator Size?

Definition: This calculator determines the BTU output required for a radiator based on temperature difference, heat transfer coefficient, and surface area.

Purpose: It helps HVAC professionals and homeowners properly size radiators for efficient heating.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — BTU output (BTU/h)
• \( \Delta T \) — Temperature difference (°F)
• \( K \) — Heat transfer coefficient (BTU/h·ft²·°F)
• \( A \) — Surface area (ft²)

Explanation: The temperature difference between radiator and room is multiplied by the radiator's heat transfer characteristics and its surface area.

3. Importance of Proper Radiator Sizing

Details: Correct BTU calculation ensures efficient heating, prevents energy waste, and maintains comfortable room temperatures.

4. Using the Calculator

Tips: Enter the temperature difference (typically 50-70°F), heat transfer coefficient (default 5.0 for standard radiators), and radiator surface area. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is ΔT in radiator calculations?
A: ΔT is the difference between radiator surface temperature and desired room temperature (e.g., 180°F radiator - 70°F room = 110°F ΔT).

Q2: What K value should I use?
A: Standard radiators use 5.0, while finned-tube radiators might use 3.5-4.5. Check manufacturer specifications.

Q3: How do I measure radiator surface area?
A: Calculate total exposed surface area including fins and tubes. Manufacturers often provide this data.

Q4: Does this account for room insulation?
A: No, this calculates radiator output only. Heat loss calculations should consider insulation separately.

Q5: How much extra capacity should I add?
A: Typically add 10-20% to the calculated BTU output for safety margin and faster warm-up times.