1. What is a Combi Boiler kW Calculator?

Definition: This calculator estimates the required size of a combi boiler in kilowatts (kW) based on the heat output in British Thermal Units per hour (BTU/h).

Purpose: It helps homeowners and heating professionals determine the appropriate boiler size for efficient heating system design.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( P_{kW} \) — Boiler size in kilowatts (kW)
• \( Q_{btu} \) — Heat output in British Thermal Units per hour (BTU/h)
• 3412 — Conversion factor from BTU/h to kW

Explanation: The heat output in BTU/h is divided by 3412 to convert it to kilowatts, which is the standard unit for boiler sizing.

3. Importance of Proper Boiler Sizing

Details: Correct boiler sizing ensures energy efficiency, proper heating performance, and prevents issues from undersizing or oversizing.

4. Using the Calculator

Tips: Enter the heat output in BTU/h (typically calculated based on room size, insulation, and climate). The value must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why convert BTU/h to kW?
A: kW is the standard unit for boiler sizing in most countries, while BTU/h is commonly used in heat loss calculations.

Q2: How do I find my heat output in BTU/h?
A: Use a heat loss calculator or consult with a heating professional who can assess your property's requirements.

Q3: What's a typical kW range for residential combi boilers?
A: Most homes require combi boilers between 24-35 kW, but this varies based on property size and insulation.

Q4: Should I round up the calculated kW?
A: Yes, boilers come in standard sizes, so you'll typically need to choose the next available size above your calculation.

Q5: Does this account for hot water demand?
A: This calculates heating requirements only. Combi boilers need additional capacity for hot water - consult a professional for complete sizing.