1. What is Electric Unit Heater Sizing?

Electric unit heater sizing is the process of determining the appropriate power rating (in kW) for an electric heater based on the heat loss of the space and the efficiency of the heating system.

2. How Does the Calculator Work?

The calculator uses the electric heater sizing equation:

Where:

• \( kW \) — Required heater size in kilowatts
• \( heat\_loss \) — Total heat loss of the space in kW
• \( efficiency \) — Efficiency of the heating system (as a fraction between 0 and 1)

Explanation: The equation accounts for both the heat that needs to be replaced and the efficiency of the heating system in converting electrical energy to heat.

3. Importance of Proper Heater Sizing

Details: Proper heater sizing is crucial for maintaining comfortable temperatures, energy efficiency, and preventing equipment overload or short cycling.

4. Using the Calculator

Tips: Enter heat loss in kW and efficiency as a decimal (e.g., 0.95 for 95% efficiency). Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: How do I determine the heat loss of my space?
A: Heat loss calculations consider factors like building materials, insulation, window area, temperature difference, and air changes.

Q2: What's a typical efficiency for electric heaters?
A: Most electric resistance heaters are nearly 100% efficient (1.0), while heat pumps can have efficiencies greater than 1 (expressed as COP).

Q3: Should I add a safety factor to the calculation?
A: It's common to add 10-20% to the calculated size to account for unusual conditions or future needs.

Q4: What happens if I undersize the heater?
A: An undersized heater will run continuously but may not maintain desired temperatures in very cold conditions.

Q5: What about oversized heaters?
A: Oversized heaters may short cycle (turn on/off frequently), reducing comfort and potentially decreasing equipment life.