How much does a heat pump improve my EPC?

Replacing an old gas boiler with an ASHP typically improves SAP by 15-20 points. Replacing oil or LPG heating gives even larger improvements (20-26 points). This can jump you 1-2 EPC bands — for example, from D to C or even B. The exact improvement depends on your current heating efficiency.

What SAP score do I need for EPC band C?

Band C requires a SAP score of 69 or above. From 2025, rental properties in England and Wales are expected to meet minimum band C for new tenancies. Installing a heat pump is one of the most effective single measures to achieve this.

Does the EPC methodology favour heat pumps?

Yes, SAP 10 (the latest methodology) uses updated carbon factors that reflect the decarbonising electricity grid. This means heat pumps score significantly better than in SAP 2012. The primary energy factor for electricity has been reduced, giving heat pumps a larger SAP improvement.

Can I combine a heat pump with other measures?

Yes, combining a heat pump with insulation upgrades and solar PV can dramatically improve your EPC. For example: heat pump (+18 SAP) + cavity wall insulation (+8 SAP) + solar PV (+8 SAP) = +34 points, potentially jumping from band E to band B.

Will my EPC assessor confirm these SAP improvements?

The actual SAP improvement depends on the specific property, so the estimates here are indicative. A qualified energy assessor will run a full SAP calculation using RdSAP software. The key factors are property age, size, fabric insulation, heating system, and renewable technologies installed.

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EPC Heat Pump Calculator

Estimate how installing a heat pump will improve your EPC rating. See the SAP score uplift and predicted new energy band.

Current EPC Band

From your current EPC certificate

Current SAP Score (optional)

Leave blank to use band midpoint

Current Heating System

What the heat pump is replacing

Heat Pump Type

How We Calculate This

This calculator estimates the SAP score improvement from replacing your current heating system with a heat pump, and predicts your new EPC band.

SAP uplift estimation

Old gas boiler to ASHP: +15-18 SAP points
Oil/LPG to ASHP: +20-22 SAP points
Electric heating to ASHP: +22-25 SAP points
GSHP gives additional: +3-5 SAP points over ASHP

EPC bands

A (92-100), B (81-91), C (69-80), D (55-68), E (39-54), F (21-38), G (1-20). The UK average home is band D with SAP around 60.

Frequently Asked Questions

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Last updated: March 2026

All calculations are estimates. Verify with your supplier.