Based on data from over 140 heat pump installations YEERS has completed across Yorkshire, we can now give you a clear, evidence-based answer to the question every homeowner asks: should I replace my gas boiler with a heat pump? The answer depends on your property, your current heating costs, and whether you take the BUS grant. Here's everything you need to know.
How Heat Pumps Work — Efficiency in Plain English
A gas boiler burns fuel and converts roughly 80-95% of that fuel's energy into heat — meaning for every £1 of gas you burn, you get 80-95p worth of heat. An air source heat pump (ASHP) doesn't burn anything; it moves heat from the outside air into your home using a refrigerant cycle. For every unit of electricity the heat pump consumes, it typically delivers 2.5 to 4 units of heat — a Coefficient of Performance (COP) of 2.5 to 4.0. At COP 3.0, for every £1 of electricity you spend, you get £3 worth of heat.
The catch is that electricity costs roughly 3-4 times more per unit than gas at current tariff rates. So the heat pump's efficiency advantage needs to overcome the higher cost of the fuel it uses. Whether it does depends on your specific COP, your current gas and electricity tariffs, and how well your home retains heat.
Running Cost Comparison
For a typical four-bedroom detached home in Yorkshire with an annual heating demand of 18,000kWh:
- Gas boiler (95% efficiency, gas at 5.8p/kWh): Annual fuel cost approximately £1,100-£1,300.
- Air source heat pump (COP 3.0, electricity at 24p/kWh standard tariff): Annual electricity cost approximately £1,440. Higher than gas at standard tariffs.
- Air source heat pump on Octopus Agile (average 15p/kWh overnight charge scheduling): Annual electricity cost approximately £900-£1,000. Lower than gas, saving £200-£300/year.
The conclusion from our installation data is clear: a heat pump on a standard tariff costs more to run than gas. A heat pump on a smart tariff (Octopus Agile, Intelligent Octopus, or Cosy Octopus) costs less. This is why we always combine heat pump installations with a smart tariff discussion — and often with a solar and battery system to drive the running costs even lower.
When Heat Pumps Win — and When Gas Still Wins
Heat pumps win when: Your home has EPC C or above (good insulation reduces the heat demand), you have radiators sized for low-temperature flow (55°C or below), you're on an Octopus smart tariff, and your current gas boiler is nearing end of life anyway. With the £7,500 BUS grant reducing net cost from approximately £14,000 to £6,500, the financial case is compelling for these properties.
Gas still wins when: Your home is poorly insulated (EPC E or below) and you cannot afford to upgrade the fabric first, your radiators are undersized for low-temperature operation and would need replacing, or you're in a listed building where planning restrictions apply. In these cases, a new high-efficiency gas boiler remains the more cost-effective short-term choice, though it should be viewed as a temporary measure pending fabric improvements.
The BUS Grant — Making the Maths Compelling
The Boiler Upgrade Scheme (BUS) provides a £7,500 grant towards the cost of an air source heat pump. This grant is paid directly to your MCS-certified installer and deducted from your invoice — you never see the money, and there's no application form for you to complete. With an average installed cost of £13,000-£15,000 for a full ASHP installation including new cylinder and any necessary radiator upgrades, the BUS grant brings the net cost to £5,500-£7,500. At this price, with smart tariff savings of £200-£400/year compared to a gas boiler, payback is typically 12-18 years — comparable to a solar PV installation.
Yorkshire-Specific Considerations
Older Yorkshire housing presents specific challenges for heat pump installation. The Victorian and Edwardian terraces common in Hull, York, and Leeds have solid brick walls with high heat loss rates — heat pumps in these properties will operate at lower COP until insulation improvements are made. The post-war semis and inter-war housing common across Selby, Beverley, and the East Riding are better candidates, with cavity walls that can be insulated and higher ceiling heights that support larger radiators.
The survey process is critical. YEERS conducts a full MCS-compliant heat loss survey (to BS EN 12831) for every installation, calculating the room-by-room heat load and specifying the correct heat pump size and flow temperature. Oversizing a heat pump reduces efficiency; undersizing it means inadequate heating in cold snaps. Our surveyors have specific experience with Yorkshire's housing archetypes and the cold-weather performance requirements of a northern English climate.
Best Yorkshire Property Types for Heat Pumps
- Post-war semis (1945-1980): Cavity walls, standard ceiling heights, typically EPC D — ideal candidates once cavity wall insulation is fitted.
- Modern detached (post-1990): Already well-insulated in most cases. Straight forward heat pump installations with minimal preparation.
- Any property with cavity walls and over 80m² floor area: The combination of insulate-able walls and sufficient radiator wall space makes these the best value installations.
- Bungalows: Single-storey properties have lower heat distribution requirements, making them excellent heat pump candidates regardless of age.
View our heat pump installation service or read about the Boiler Upgrade Scheme grant.
