1. What is a System Boiler Size Calculator?

Definition: This calculator determines the required boiler size by adding the heating load and domestic hot water (DHW) load.

Purpose: It helps HVAC professionals and homeowners select an appropriately sized boiler for efficient operation.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( \text{Size} \) — Required boiler output (kW)
• \( \text{Heating Load} \) — Space heating requirement (kW)
• \( \text{DHW Load} \) — Domestic hot water demand (kW)

Explanation: The total boiler capacity must meet both the building's heating needs and hot water requirements simultaneously.

3. Importance of Proper Boiler Sizing

Details: Correct sizing ensures energy efficiency, prevents short cycling, maintains comfort, and extends equipment life.

4. Using the Calculator

Tips: Enter the heating load (from heat loss calculations) and DHW load (based on water usage patterns). Both values must be ≥ 0.

5. Frequently Asked Questions (FAQ)

Q1: How do I determine the heating load?
A: Perform a heat loss calculation considering building size, insulation, windows, and climate.

Q2: What's a typical DHW load for a family home?
A: Typically 3-5 kW for a family of 4, but varies with usage patterns and fixtures.

Q3: Should I add a safety margin?
A: Yes, consider adding 10-20% to the calculated size for extreme conditions and future expansion.

Q4: What if I have a combi boiler?
A: Combi boilers require different sizing as they prioritize DHW - use a combi-specific calculator.

Q5: Does this account for radiator sizing?
A: No, radiators must be sized separately based on room requirements and boiler output.