1. What is a Boiler Size Calculator?

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

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

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( P_{kW} \) — Boiler size in kilowatts
• \( Q_{btu} \) — Heat output requirement in BTU/hour

Explanation: The formula converts BTU/hour to kilowatts using the conversion factor of 3412 BTU/hour = 1 kW.

3. Importance of Proper Boiler Sizing

Details: Correct boiler sizing ensures efficient operation, prevents energy waste, and maintains comfort while avoiding short cycling or insufficient heating capacity.

4. Using the Calculator

Tips: Enter the required heat output in BTU/hour. The value must be greater than 0.

5. Frequently Asked Questions (FAQ)

Q1: How do I determine my heat output requirement?
A: Heat output depends on factors like home size, insulation, climate, and desired temperature. Professional heat load calculations are recommended.

Q2: What's the typical BTU requirement for a house?
A: A rough estimate is 30-60 BTU per square foot, but this varies significantly based on climate and insulation quality.

Q3: Why convert to kW when boilers are often rated in BTU?
A: Many modern boilers use kW ratings, especially in Europe and for high-efficiency models. This conversion allows comparison across different systems.

Q4: Should I round up the boiler size?
A: It's common practice to round up to the nearest standard boiler size, but oversizing by more than 15% can reduce efficiency.

Q5: Does this account for domestic hot water needs?
A: No, this calculates space heating requirements only. Additional capacity may be needed for water heating.