1. What is a BTU Calculator?

Definition: This calculator estimates the heating load required for a space based on temperature difference, heat transfer coefficient, and surface area.

Purpose: It helps HVAC professionals and homeowners determine the appropriate heating capacity needed for a room or building.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Heating load (Watts or BTU/h)
• \( \Delta T \) — Temperature difference between inside and outside (°C)
• \( K \) — Heat transfer coefficient (W/m²·K)
• \( A \) — Surface area of the space (m²)

Explanation: The temperature difference multiplied by the heat transfer coefficient and surface area gives the heat loss through the building envelope.

3. Importance of Heating Load Calculation

Details: Proper heating load estimation ensures comfortable indoor temperatures, energy efficiency, and correct sizing of heating equipment.

4. Using the Calculator

Tips: Enter the temperature difference, heat transfer coefficient (default 0.33 W/m²·K for insulated walls), and surface area. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical K value for walls?
A: Well-insulated walls: 0.33 W/m²·K, Single-glazed windows: 5.7 W/m²·K, Brick walls: ~1.3 W/m²·K.

Q2: How do I determine ΔT?
A: Subtract the lowest expected outdoor temperature from your desired indoor temperature.

Q3: Should I include all surfaces in area calculation?
A: Yes, calculate total external wall, window, roof, and floor areas that lose heat.

Q4: How do I convert Watts to BTU/h?
A: 1 Watt = 3.412 BTU/h (automatically calculated in results).

Q5: Does this include ventilation heat loss?
A: No, this calculates transmission heat loss only. Add 10-20% for ventilation losses.