In the UK today, heat pump running costs are generally competitive with gas boilers, though the outcome depends on several critical factors. Under current price-cap rates (electricity around 24.5–27.7p/kWh, gas around 5.9–6.4p/kWh), a heat pump with a typical seasonal coefficient of performance (SCOP) of 3.0–4.0 delivers heat at an effective cost of roughly 7–9p per kWh [1]. This compares closely to a modern gas boiler operating at ~90% efficiency, which delivers heat at approximately 6.5–7.1p per kWh. The narrow margin means heat pumps are often slightly more expensive on standard tariffs, but this changes significantly with dedicated heat pump tariffs.

Dedicated off-peak electricity tariffs (14–20p/kWh) offered by suppliers like Octopus Energy or British Gas can tip the balance decisively in favour of heat pumps. Additionally, households that remove their gas meter save £100–£130 annually by avoiding standing charges [1]. Real-world data suggests that approximately 80% of homes using smart tariffs paid less to heat with a heat pump than with gas, though this figure applies to that specific sample and should not be generalised to all UK homes [1].

However, several conditions must be met for heat pumps to deliver cost savings. Poor home insulation, old radiators, or low-quality installation can reduce effective SCOP below 2.8, making gas boilers cheaper to run. The quality of installation and the home's thermal characteristics are therefore as important as the equipment itself. Running-cost estimates are also sensitive to energy prices, which fluctuate, and to individual consumption patterns. For most well-insulated homes with good installation and access to favourable electricity tariffs, heat pumps offer running costs comparable to or lower than gas boilers, with the added benefit of long-term protection against volatile gas prices.