As you may know, heat pumps aren’t cheap. The Energy Saving Trust estimates that a typical air source heat pump installation will set you back around £6000 – £8000, and a ground source system by £10,000 – £18,000 depending on the amount of heat required. The question is, are they worth it? Considering you can receive up to £8,400 from the domestic RHI for an air source heat pump, and as much as £26,600 for a ground source system – not to mention savings on fuel bills – we certainly think so.
So what’s the reason for this hefty price tag? In this article, we take a closer look at the various costs associated with heat pumps, and how they compare with other forms of central heating.
The first potential cost in the process of buying a heat pump is the initial site visit. This is where the installer comes to your home to assess whether a heat pump will be suitable (ground source or air source). The installer will then leave to put a quote together.
It’s at the installer’s discretion to charge for this initial survey. However you may find, as is often the case, that this service is free of charge.
Here’s an idea of what a heat pump’s running costs could look like per kilowatt hour of thermal energy. These figures may not mean very much on their own, so we’ve put them next to some other typical forms of central heating and their respective boiler efficiencies:
Heat generator efficiency
Type of fuel
Cost of fuel (p/kWh)
Running cost (p/kWhth)
|Air source heat pump||SCoP 3.36||Electricity||14.37||4.28|
|Ground source heat pump||SCoP 3.36||Electricity||14.37||4.28|
|Electric storage heater||98%||Electricity||14.37||14.08|
p/kWhth = pence per kilowatt hour of thermal energy
SCoP = Seasonal Coefficient of Performance.
Cost of fuels sourced from Energy Saving Trust, correct as of May 2017
As you can see, even with a fairly average SCoP, both types of heat pump can drastically cut heating bills for those currently using electric storage heaters (approx. 69% cheaper than what you’re currently paying).
What’s more, a well-designed system with a flow temperature of 40oC or even 35oC in a properly insulated home is capable of achieving an SCoP of 4 and over. Couple that with an Economy 10 or 7 electricity tariff and a savvy approach to using your heat pump (timing it to turn on during off-peak electricity times), and you should see your heating bills drop to lower than LPG or even mains gas bills.
Taking it one step further, generating your own electricity would significantly reduce the running costs of a heat pump. From a consumption perspective, installing solar panels could effectively see your heat pump working at a CoP of 7 or above.
That may sound like a lot of ifs and buts, “but” one of the main issues is that the cost of electricity is high. This issue was raised by Dieter Helm in his government-commissioned “Cost of Energy Review”. At present, the UK is in a period of decarbonising its electricity supply chain. Whilst electricity-generating coal-fired power stations are closing ahead of the government’s plans to shut them all by 2025, it stands to reason that the price of electricity is rising. However, with the cost of renewable technology significantly reducing, and with more solar farms, battery storage and wind farms emerging throughout the UK, the cost of electricity is likely to reduce in the future.
Unsurprisingly, digging up a large portion of your garden does come at a cost. This is the main reason why ground-source heat pumps are considerably more expensive to buy than air-source systems. The cost further increases if you install a vertical ground loop system (boreholes).
However, with a ground-source heat pump comes the increased domestic RHI rates, and with it, the quicker payback period. You also get the assurance of maintaining a year-round Coefficient of Performance, unlike with air-source heat pumps that fluctuate through the seasons.
Models of heat pumps have different Total Installed Capacities (a number of kilowatts will be given e.g. “8kW air source heat pump”), so the price is usually compared per kilowatt. As a general guide, you should expect to pay:
Type of heat pump
Cost per kilowatt (parts and installation)
|Air source heat pump||£900|
|Ground-source heat pump||£1,300|
Costs are indicative and are stated for information use only. Figures may vary, does not include additional heat distribution modifications.
Keep in mind that the cost per kW reduces as the Total Installed Capacity increases. For instance, you could be quoted for £1200 per kilowatt to install a small 5kW air source heat pump, but just £600 per kilowatt for a 16kW system. The cost may be greater still if you’re installing a vertical ground loop system.
The installation of a heat pump is often tied in with several other home improvements to keep the overall costs down and to achieve a high efficiency. These improvements can be renovating the garden if it’s a ground source heat pump, or improving the efficiency of the house by installing insulation.
Perhaps the best improvement to accompany a heat pump installation is underfloor heating. Besides improving the comfort of your home, its large surface area makes it an ideal method of distributing heat evenly. This in turn reduces the flow temperature required, so it’s great for maintaining a high efficiency. The only downside is the upfront cost, which is usually above £2000 depending on the size of your house.
Unfortunately, it’s tricky to give a definitive answer on how much the system will cost for your house overall. The price is contingent on the individual house, and even very similar properties can have very different heating requirements.
The cost of installation will vary significantly, so it’s always best to gather a number of quotes together from different installers and pick which one is best for you. Click here if you’d like to find an installer near you.