1. What is a Combi Boiler BTU Calculator?

Definition: This calculator estimates the total BTU (British Thermal Units) requirement for a combi boiler by adding hot water demand and heating demand.

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

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( BTU \) — Total boiler capacity required (BTU/h)
• \( \text{Hot Water Demand} \) — BTU needed for domestic hot water
• \( \text{Heating Demand} \) — BTU needed for space heating

Explanation: Combi boilers must meet both hot water and heating demands simultaneously, so their capacity is the sum of both requirements.

3. Importance of Proper BTU Calculation

Details: Correct sizing ensures energy efficiency, adequate heating performance, and prevents short cycling of the boiler.

4. Using the Calculator

Tips: Enter the hot water demand and heating demand in BTU/h. Both values must be ≥ 0. For accurate results, calculate each component separately.

5. Frequently Asked Questions (FAQ)

Q1: How do I determine hot water demand?
A: Calculate based on the number of bathrooms and simultaneous fixtures. A typical shower requires about 30,000 BTU/h.

Q2: How do I calculate heating demand?
A: Perform a heat loss calculation considering your home's size, insulation, windows, and climate.

Q3: What's the typical BTU range for residential combi boilers?
A: Most residential units range from 60,000 to 150,000 BTU/h, depending on home size and climate.

Q4: Should I add a safety margin?
A: It's common to add 10-20% to the calculated BTU for extreme weather conditions.

Q5: What if my calculated BTU falls between standard sizes?
A: Always round up to the next available boiler size to ensure adequate capacity.