Heat pump vs gas boiler: the real comparison
These two heat your home in completely different ways. Here's an honest, side-by-side look.
A gas boiler burns fuel to make heat. A heat pump moves heat from the outside air. That fundamental difference drives everything else.
Efficiency
A gas boiler is always under 100% efficient — you get less heat out than the energy you put in. A heat pump delivers around 300–400% — three to four units of heat per unit of electricity. It's not magic; it's moving existing heat rather than creating it.
Running costs
Electricity costs more per unit than gas, so the efficiency advantage is partly offset. In a well-insulated home a heat pump can be cheaper to run; in a poorly insulated one, the gap narrows. Insulation is the deciding factor.
Upfront cost
Heat pumps cost more to install than boilers — the Energy Saving Trust puts a typical air source heat pump at around £11,000 — but the Boiler Upgrade Scheme grant (£7,500, or £9,000 for oil/LPG homes) closes much of that gap.
The bottom line
If your home is well insulated and you want lower carbon and future-proofing, a heat pump makes increasing sense — especially with the grant. If not, insulate first.
What about your radiators?
Heat pumps run at lower flow temperatures than boilers, which means they heat water to a gentler temperature and run for longer, steadier periods. In some homes, this means a few radiators need upsizing to deliver the same warmth — something we'd assess at survey. It's not a dealbreaker, just part of designing the system properly.
Which is right for you?
- Well-insulated home, want lower carbon, eligible for the grant → heat pump makes strong sense.
- Poorly insulated home → insulate first, then reconsider.
- Need a like-for-like quick replacement now → an efficient boiler may suit better for now.