GUIDE
Combi swap versus heat pump versus PV
Last checked September 2026
A like-for-like combi in the same cupboard is the cheap job in 2026 guides: compiled mid about £2,800 before VAT and contingency. Relocation is an add-on. A system / regular boiler sits higher (mid about £3,800) because cylinders and open-vented pipework get involved.
An air-source heat pump for a typical house is a different band — compiled mid about £13,000 before grants. Government support sits outside the range; do not net a grant off in this tool.
Solar PV is priced per kWp (default 4 kWp, mid about £1,650 / kWp). A battery is a separate line per kWh.
Some energy-saving measures can attract 5% or 0% VAT. That is a user choice in the calculator, not a determination.