Your Home Climate

Heat pumps · vs gas boiler7 min

Heat pump or gas boiler; which is genuinely the right choice for a UK home in 2026?

Short answer

For most owner-occupied UK homes that have made the obvious insulation moves, a heat pump is the better answer once the £7,500 grant is applied and a heat-pump tariff is in place. A boiler is still the right choice when the fabric can't carry a heat pump economically or when the household genuinely cannot switch electricity tariff.

Evidence

  • Fact

    Boiler Upgrade Scheme grant for an air- or ground-source heat pump

  • Fact

    Air-source heat pump SCOP (well-designed UK installation)

  • Fact

    Ofgem default tariff cap; unit rate

  • Source

    Energy Saving Trust

    Independent UK organisation publishing energy efficiency guidance.

    Field-trial evidence on running-cost outcomes across mixed housing stock.

  • Source

    Octopus Energy tariff documentation

    Published tariff documentation for the Cosy Octopus heat pump tariff, used only when quoting that tariff's published rates and structure.

    Heat-pump tariff data that closes most of the running-cost gap.

Every number on this page resolves through our knowledge graph: Fact, Claim, Cost or Source. Nothing is asserted without a trail back to its origin.

Decision guidance

The comparison has three axes: up-front cost, running cost across the system's life, and the direction of travel for the fuel it uses. Ignoring any one of them produces the wrong answer.

When this applies

  • The house has cavity or loft insulation done to a reasonable standard.
  • The £7,500 BUS grant is available and the property qualifies.
  • The household can move to a heat-pump-specific electricity tariff.
  • You expect to live in the property long enough to see the running-cost delta pay back the install premium (typically seven to twelve years without a grant, much sooner with).
  • You care about the carbon trajectory of the heating fuel across the next decade, not just today's unit rate.

When it doesn't

  • The fabric is genuinely un-improvable within budget and the heat-loss calculation forces a flow temperature that makes SCOP unrealistic.
  • You cannot switch electricity supplier or tariff.
  • There is no external wall or garden space for an outdoor unit compliant with permitted development.
  • You are actively planning to sell within two years; the payback horizon doesn't work.

Practical detail

The up-front cost picture, honestly.

A new gas combi installed by a Gas Safe engineer typically comes in between £2,800 and £4,500 in 2026. An MCS heat-pump install lands between £11,000 and £15,000 before the grant, and roughly £4,500 to £8,500 after it. On post-grant numbers the heat pump costs one and a half to two boilers, not three. That gap changes the payback conversation entirely.

The running-cost picture, honestly.

On a standard variable electricity tariff and a designed SCOP of 3.5, a heat pump runs close to level with a modern condensing boiler across the year in a reasonably insulated three-bed semi. On a heat-pump-specific tariff, the same pump in the same house runs roughly twenty to thirty per cent cheaper than gas. The tariff is doing most of the work, not the technology on its own.

The variable that swings the answer harder than any other is the SCOP the system actually achieves. A poorly designed install can drop to 2.8 or below, which puts it behind a good boiler on any tariff. A well-designed install can reach 4.5 in a modern home, which puts it comfortably ahead on almost any tariff.

The direction of travel that changes over time.

Gas is priced against wholesale gas, which is exposed to geopolitics and to long-run supply decline. Electricity is decarbonising each year as more renewables displace gas generation, and the unit-rate structure of heat-pump tariffs is moving further from the standard cap, not closer. A heat pump you install today is on a curve that quietly improves for the next decade; a boiler is on one that quietly worsens.

When the boiler is still the right answer.

The honest cases for a boiler in 2026 are: a house whose fabric genuinely cannot support a heat pump economically; a household that cannot or will not switch electricity tariff; a short-tenure situation where the payback horizon does not close; and any case where a hybrid would be a better bridge than either. None of these are the default case, but they are all real.

The full picture

Reference page

Heat pumps: the full decision

The full decision framework this guide sits under.

Related guides

Open the heat-pump sizing planner

Model your home before comparing quotes; without a sizing figure the comparison is guesswork.