The debate between heat pumps and gas boilers has become central to the UK’s home decarbonisation agenda. With the government pushing for heat pump adoption and gas boiler sales set to end in new-build homes, millions of homeowners are trying to work out whether switching makes financial sense. Here is an honest cost comparison for 2026.
Installation Costs
A gas boiler replacement typically costs £2,000–£4,000 installed in the UK, depending on the model and any pipework modifications required. An air-source heat pump installation, by contrast, costs £8,000–£15,000 — though the Boiler Upgrade Scheme (BUS) grant currently provides £7,500 toward the cost, reducing the net cost to £500–£7,500 for qualifying homes and systems.
Running Costs: The Critical Comparison
This is where the comparison becomes nuanced. Heat pumps run on electricity costs, which currently significantly more per unit of energy than gas in the UK. A gas boiler might achieve efficiency of around 90%, paying 6–7p per kWh of heat delivered. A heat pump, despite being 250–350% efficient (delivering 2.5–3.5 units of heat per unit of electricity consumed), pays the higher electricity rate of around 24–28p per kWh consumed.
The net result: for many UK homes, running costs for heat pumps and gas boilers are broadly comparable at current energy prices, though the heat pump advantage grows in well-insulated homes where the system can run at higher efficiency.
The Long-Term Calculation
Over a 15–20 year lifetime, a heat pump installed with BUS grant support is likely to be cost-competitive with a gas boiler for most UK homeowners, particularly as electricity prices are expected to fall relative to gas as renewable energy grows. For new builds and highly insulated homes, the economics are clearly favourable today.
This article is for informational purposes only and does not constitute financial or investment advice. Always consult a qualified financial adviser before making investment decisions.
