1. What is a kW Calculator for Room Heating?

Definition: This calculator estimates the power (in kW) required to heat a room based on U-value, surface area, and temperature difference.

Purpose: It helps HVAC professionals and homeowners determine appropriate heating system capacity for a space.

2. How Does the Calculator Work?

The calculator uses the formulas:

Where:

• \( Q \) — Heat requirement (Watts)
• \( U \) — U-value (W/m²K)
• \( A \) — Surface area (m²)
• \( \Delta T \) — Temperature difference (Kelvin)
• \( kW \) — Power requirement (kilowatts)

Explanation: The U-value represents heat transfer coefficient, multiplied by area and temperature difference gives heat loss in watts, which is converted to kW.

3. Importance of kW Calculation

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

4. Using the Calculator

Tips: Enter the U-value (thermal transmittance), total surface area of the room, and desired temperature difference between inside and outside.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical U-value for walls?
A: Modern insulated walls: 0.2-0.3 W/m²K, older walls: 1.0-1.5 W/m²K, single-glazed windows: ~5.0 W/m²K.

Q2: How do I calculate total surface area?
A: Sum the areas of all walls, floor, ceiling, windows and doors that lose heat to the outside.

Q3: What temperature difference should I use?
A: Difference between desired indoor temperature and coldest expected outdoor temperature (e.g., 20°C inside, -5°C outside → ΔT = 25K).

Q4: Does this include ventilation losses?
A: No, this calculates only conduction losses. Add 10-20% for air infiltration or use more detailed calculations.

Q5: How do I convert kW to BTU/h?
A: Multiply kW by 3412.142 to get BTU/h (1 kW = 3412.142 BTU/h).