Heat Pumps vs. Gas Boilers: Which is Right for Your Home?

The UK government has set a target to phase out new gas boiler installations from 2035. Meanwhile, heat pumps are being promoted as the primary alternative. But is a heat pump right for your home right now? This is a genuinely nuanced question — and the honest answer is: it depends significantly on your home's insulation, your heating habits, and your local electricity tariff.

A gas boiler burns gas to heat water, which is then pumped around radiators and hot water cylinders at temperatures typically between 60-80°C. A heat pump (air source or ground source) extracts heat energy from the outside air or ground and concentrates it, delivering water at lower temperatures (typically 35-55°C). This is why heat pumps generally perform best with underfloor heating or oversized radiators designed for lower flow temperatures.

A modern gas boiler operates at around 90-95% efficiency — for every unit of gas energy burned, 90-95% is converted to useful heat. A heat pump achieves a Coefficient of Performance (COP) of 2.5-4.0 — for every unit of electricity used, 2.5-4 units of heat are delivered. However, electricity costs approximately 3-4 times more per kWh than gas in the UK, which means the running cost advantage is less clear-cut than the efficiency figures suggest.

Heat pumps are highly efficient, but their economic case depends heavily on the ratio of electricity to gas prices. As that ratio falls — through cheaper renewable electricity — the financial case for heat pumps will strengthen.

— Energy Saving Trust

Heat pumps work best in well-insulated homes with large heat emitters (underfloor heating or oversized radiators). They can work in older, less well-insulated homes, but may require a higher-than-ideal flow temperature — reducing efficiency. A heat loss calculation (carried out by an MCS-certified heat pump installer) will tell you the heat demand of your home and whether a heat pump can meet it economically.

An air source heat pump typically costs £8,000-£15,000 to supply and install. Ground source heat pumps (which use buried loops) cost £15,000-£35,000+. The Boiler Upgrade Scheme (BUS) currently offers a £7,500 grant for air source heat pumps and £7,500 for ground source heat pumps in England and Wales. This substantially improves the payback period but is subject to scheme availability.