Heat pump vs gas boiler: what it does to your EPC
Replacing gas heating with a heat pump almost always improves a commercial EPC rating, but only pays back where the fabric and emitter temperatures suit low-flow-temperature heating.
Heating replacement is the most common single measure proposed in MEES uplift plans, and the most commonly mis-specified. The carbon factor of grid electricity has fallen far below gas, so the modelled rating improves. Real running cost is a different question, governed by the achieved seasonal coefficient of performance, which collapses if the system is asked to run at boiler flow temperatures into undersized emitters.
Heat pump vs Gas boiler, attribute by attribute
| Attribute | Heat pump | Gas boiler |
|---|---|---|
| Effect on EPC rating | Usually improves, often by a band | Baseline |
| Carbon in use | Low and falling with the grid | Fixed and comparatively high |
| Running cost | Depends on SCOP and tariff | Currently lower per kWh |
| Fabric dependency | High — needs low flow temperatures | Low |
| Plant space and power supply | Larger; may need supply upgrade | Modest |
| Capital cost | Higher | Lower |
Which one applies to you
Choose Heat pump when
- /Fabric is being upgraded at the same time
- /Emitters can be resized or the building is already low-temperature
- /Net zero commitments or planning policy require fossil-fuel-free heating
Choose Gas boiler when
- /Short remaining hold period with no rating pressure
- /Electrical supply capacity or plant space genuinely prevents a heat pump
We model the measure inside the building's own EPC or DSM model before recommending it, so the predicted band change and the required emitter and supply works are known before procurement.
Common questions
+Will a heat pump guarantee EPC B?
No. It moves the rating in the right direction, but poor fabric, inefficient lighting or high ventilation losses can still hold a building below B.