New boiler or heat pump? An honest comparison for 2026

Updated 1 July 2026

With the Boiler Upgrade Scheme knocking £7,500 off an air source heat pump, plenty of homeowners are asking whether a like-for-like boiler swap is still the right call. Sometimes it is, sometimes it isn't — here's the honest version from a company that only sells boilers.

The headline numbers

A replacement boiler typically costs £1,900–£3,600 fitted, and works with your existing radiators and pipework.

An air source heat pump typically costs £11,000–£16,000 before the grant — so roughly £3,500–£8,500 after the £7,500 Boiler Upgrade Scheme in England and Wales — and often needs larger radiators, a hot water cylinder, and better insulation to perform well.

Where heat pumps genuinely win

In a well-insulated home with space for a cylinder and outdoor unit, a properly designed heat pump is 3–4× as efficient as a gas boiler and can cost less to run, especially on a heat-pump-specific electricity tariff.

If you're renovating anyway — new radiators, new floors, insulation — that's the cheapest moment you'll ever have to switch, and the grant makes the sums genuinely competitive.

Where a boiler still makes sense

If your boiler has died in December, a like-for-like swap gets heat back on tomorrow; a well-designed heat pump installation takes weeks of surveys and radiator changes.

In draughty, poorly insulated homes, a heat pump runs hard and the running-cost advantage shrinks or disappears. Insulate first, then electrify — in that order.

In flats and small terraces without outdoor space or room for a cylinder, a combi boiler often remains the only practical option.

A fair way to decide

Ask three questions: How urgent is the replacement? How well insulated is the home? Is there space for a cylinder and outdoor unit? Two or more answers in the boiler column usually means swap now and plan the heat pump for a future renovation — boilers fitted today will be replaceable by cheaper, better heat pumps in 10–12 years.

If you're leaning heat pump, use an MCS-certified installer and get a full heat-loss survey — not a quote over the phone. The grant requires MCS certification anyway.

This guide is general information, not a survey of your home. Anything involving gas must be done by a Gas Safe registered engineer.