Boiler Sizing Calculator — Find the Right Boiler Size for Your Home

Boiler Sizing Calculator

Calculate the optimal boiler size for your home based on property size, insulation, number of radiators, and heating requirements.

Step 1: Property Details

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Understanding Property Size

Larger properties require more powerful boilers to adequately heat all rooms. Measure the total floor area of all rooms you want to heat, excluding unheated spaces like garages.

Step 2: Heating Requirements

About Insulation Levels

Well-insulated homes retain heat better and require smaller boilers. Modern insulation can reduce boiler size requirements by 20-30% compared to poorly insulated properties.

Boiler Sizing Results

Summary
Size Comparison
Requirements Analysis

Recommended Boiler Size

24 kW
Suitable for: 120 m² Property
Heating Requirement
15 kW
Hot Water Requirement
9 kW
Estimated Efficiency
92%
Annual Running Cost
£850

Boiler Size Comparison

Property Type Size Range Boiler Size Radiators Annual Cost

Heating Requirements Analysis

Boiler Sizing Formula

Total kW = (Property Area × Heat Loss Factor) + Hot Water Demand

The boiler size is calculated by determining your property’s heat loss (based on size and insulation) and adding the hot water requirements for your household size and usage patterns.

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