Efficiency first
Every kilowatt-hour of heat you don't need is one you never have to generate, whatever the technology. Reducing demand before replacing a boiler means a smaller, cheaper heat pump that runs more efficiently. Typical steps include:
- Fix controls: correct time schedules, sensible setpoints, zoning, and stopping heating and cooling fighting each other.
- Insulate pipework, valves and hot water tanks, especially in plant rooms.
- Draught-proof, fit door closers or air curtains on loading bays, and fix broken windows and rooflights.
- Improve roof and wall insulation when refurbishment work is planned anyway.
- Recover waste heat from compressors, refrigeration and processes.
- Balance the heating system so it works at lower flow temperatures.
Heat pumps for buildings
A heat pump uses electricity to move heat from outside air, the ground or water into a building, using the same refrigeration cycle as a fridge in reverse. Because it moves heat rather than creating it, a well-designed system typically delivers roughly 2.5–4 units of heat per unit of electricity over a year. That ratio is called the seasonal coefficient of performance (SCOP).
Types used by businesses
- Air-source (air-to-water): replaces a boiler in wet radiator or underfloor systems. The most common retrofit choice.
- Air-to-air (VRF/split systems): widely used in offices and retail; can heat and cool, and is often already installed for cooling.
- Ground- or water-source: higher installation cost but more stable efficiency in cold weather; suits sites with land, boreholes or a nearby water body, and larger shared ground loops.
- High-temperature heat pumps: can supply higher flow temperatures for older buildings or hot water, at some efficiency cost.
Design matters more than the box. Heat pumps run most efficiently at lower flow temperatures, which may mean larger radiators or emitters in some rooms. A proper heat-loss calculation, not a like-for-like swap for the boiler's rating, is essential. Poorly designed systems are the main cause of disappointing results.
Running costs: the price ratio
Per kilowatt-hour, electricity in the UK has typically cost several times as much as gas. Whether a heat pump is cheaper to run therefore depends on whether its efficiency outweighs that price gap. As a rule of thumb, divide your electricity unit price by your gas unit price. If the heat pump's SCOP (adjusted for your boiler's efficiency) is higher than that ratio, running costs should fall; if lower, they may rise.
Ways to tip the balance: on-site solar, time-of-use tariffs with thermal storage, and good system design that pushes the SCOP up. Carbon savings are usually substantial regardless, because UK grid electricity has become much lower-carbon than burning gas directly. The estimator lets you test the ratio with your own prices.
Electrifying process heat
Manufacturers, food producers, laundries and others use gas for process heat: ovens, dryers, washers, steam boilers, furnaces. Electrification options depend on the temperature needed:
| Temperature range | Typical uses | Electric options |
|---|---|---|
| Below ~100°C | Washing, pasteurising, drying, space and water heating | Industrial heat pumps, often using recovered waste heat as their source |
| ~100–200°C | Low-pressure steam, some drying and cooking | High-temperature and steam-generating heat pumps, electric boilers, mechanical vapour recompression |
| Above ~200°C | Baking, metals, glass, ceramics | Electric resistance, induction, infrared, electric arc and plasma; thermal storage |
Process changes can bring benefits beyond carbon: induction and infrared heat faster and more precisely, and electric ovens can improve product consistency. The main barriers are capital cost, grid capacity (a large process load can need a significant connection upgrade), and the gas-to-electricity price ratio for technologies that don't benefit from heat pump efficiency. Start by eliminating steam where it's used only by habit, reducing temperatures where the process allows, and recovering waste heat.
What about hydrogen?
Hydrogen is sometimes presented as a drop-in replacement for natural gas. For space heating in ordinary buildings, most independent analysis finds electrification through heat pumps to be more efficient and cheaper, because making hydrogen from electricity and then burning it loses much of the energy. Hydrogen may have a role in specific high-temperature industrial processes and in industrial clusters. Whether and where it will be available to businesses at scale remains uncertain, so waiting for it is a risky plan for most.
Planning the switch
- Survey heat demand and understand when and where heat is used.
- Reduce demand using the steps above.
- Check electrical capacity early; connection upgrades can take months.
- Plan for end of life: have a heat pump design ready so a failed boiler isn't replaced like-for-like in an emergency.
- Consider hybrid as a stepping stone where full electrification is hard now.
- Commission and monitor: metering lets you prove performance and fix problems.