Heat pump in a terraced house
Two neighbours means two fewer exposed walls, so heat demand is lower than the floor area suggests. The usual obstacle is finding somewhere for the outdoor unit and a hot water cylinder.
With the radiators as they are
Saves £75
a year · existing radiators, average size
With upgraded radiators
Saves £182
a year · SCOP 3.4
What to do first
Space planning matters more than the heat loss calculation here. Measure where the cylinder goes before getting attached to the idea.
Upgrading the radiators is worth about £107 a year in this house — which is the difference between a heat pump being a good idea and a questionable one.
The numbers behind that
- Typical gas use for this kind of house: about 9,500 kWh a year.
- That is roughly 8,075 kWh of actual heat, once boiler losses are taken off.
- A heat pump on the existing radiators would use about 2,784 kWh of electricity to deliver it.
- Break-even electricity price: 28.81p per kWh. The cap is currently 26.11p.
If your break-even price is above the price you actually pay, the heat pump wins. If it is below, it does not — and no amount of enthusiasm changes that arithmetic. A dedicated heat pump tariff can move your real price down enough to flip it.