Heat Pump Size Calculator

Estimate whole-home heat loss and a practical heat pump size using UK-style factors and climate region adjustments.

Units

Floor area (m²)

Property type

Property age

Insulation quality

Insulation upgrades

Multipliers: loft ×0.92, wall ×0.88.

Glazing

Multipliers: single ×1.12, triple ×0.94.

UK region

Results

Recommended heat pump size

Estimated heat loss

4.97 kW

Recommended size

6 kW

Acceptable range: 5–7 kW (one standard size either side)

MCS survey recommended

Always confirm sizing with an MCS-accredited heat loss survey to validate heat pump capacity, radiator suitability, and flow temperature requirements.

BUS grant eligibility

Likely eligible (houses/bungalows typically qualify). Confirm your property and installer eligibility for the Boiler Upgrade Scheme.

Cost estimate (after £7,500 grant)

Size band	Typical range
5–7 kW	£500–£3,500
8–10 kW	£2,500–£6,500
12–14 kW	£5,500–£10,500
16 kW+	£8,500–£14,500

These are broad estimates and vary by emitter upgrades, cylinder, controls, and fabric improvements.

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