1. What is a Boiler Sizing Calculator?

Definition: This calculator determines the required boiler power in kilowatts (kW) based on the heat requirement in British Thermal Units per hour (BTU/h).

Purpose: It helps homeowners and HVAC professionals properly size a boiler for residential heating systems.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( P_{kW} \) — Boiler power (kilowatts)
• \( Q_{btu} \) — Heat requirement (BTU per hour)
• 3412 — Conversion factor from BTU/h to kW

Explanation: The heat requirement in BTU/h is converted to kilowatts by dividing by 3412 (since 1 kW = 3412 BTU/h).

3. Importance of Proper Boiler Sizing

Details: Correct boiler sizing ensures efficient operation, prevents energy waste, and maintains comfortable indoor temperatures.

4. Using the Calculator

Tips: Enter your home's heat requirement in BTU/h. The value must be > 0. Common residential boilers range from 30,000 to 150,000 BTU/h.

5. Frequently Asked Questions (FAQ)

Q1: How do I determine my home's heat requirement?
A: A professional heat loss calculation is best, or use 30-60 BTU per sq ft (colder climates need higher values).

Q2: Why convert BTU/h to kW?
A: Many boiler specifications use kW, especially in metric countries, while heat loss calculations often give BTU/h.

Q3: Should I round up the boiler size?
A: Yes, it's common to round up to the nearest standard boiler size for a safety margin.

Q4: What's the conversion factor 3412?
A: It's the exact conversion - 1 kW = 3412.142 BTU/h (the calculator uses the rounded value for simplicity).

Q5: Does this account for domestic hot water?
A: No, this calculates heating needs only. Add 10-20% if the boiler also supplies hot water.