1. What is a Combi Boiler kW Calculator?

Definition: This calculator converts heat output in BTU/h to boiler power in kilowatts (kW) to help determine the appropriate combi boiler size.

Purpose: It helps homeowners and heating professionals select the correctly sized combi boiler for efficient heating and hot water production.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( P_{kW} \) — Boiler power (kilowatts)
• \( Q_{btu} \) — Heat output (BTU per hour)

Explanation: The conversion factor 3412 represents the number of BTUs per hour equivalent to 1 kW of power.

3. Importance of Proper Boiler Sizing

Details: Correct boiler sizing ensures energy efficiency, adequate hot water supply, and prevents short cycling (frequent on/off operation).

4. Using the Calculator

Tips: Enter your heat requirement in BTU/h. For whole-house calculations, first determine your home's total heat loss.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical BTU requirement for a house?
A: A 2,000 sq ft home might need 60,000-80,000 BTU/h, but this varies by climate and insulation.

Q2: How many kW is a typical combi boiler?
A: Most residential combi boilers range from 24-42 kW (82,000-143,000 BTU/h).

Q3: Why convert BTU to kW?
A: UK/EU boiler ratings use kW, while heat loss calculations often produce BTU values.

Q4: Should I round up the kW result?
A: Yes, choose the next available boiler size (manufacturers offer standard kW sizes).

Q5: Does this account for hot water demand?
A: Combi boilers must meet both heating and instantaneous hot water needs - consult a professional for sizing.