How much do heat pumps cost to run?
One question that frequently comes up is how much heat pumps cost to run.
After all, this is likely to be a big factor in your decision if you’re toying with the idea of switching your boiler for a commercial heat pump.
Here, we’ll give you an idea and compare the cost of running an air source heat pump vs a gas boiler.
How much do heat pumps cost to run?
It’s difficult to put an exact figure on how much heat pumps cost to run.
This is because there are so many different variables to take into account.
However, one thing we can say is that heat pumps typically cost less to run than the average gas boiler.
Why?
Well, heat pumps are much more efficient. While the most efficient gas boilers can reach around 98% efficiency, air source heat pumps can reach around 300% efficiency.
If you’re wondering how that’s possible, consider that heat pumps don’t actually generate heat from scratch. Instead, heat pumps work by transferring heat from one place to another, using just a small amount of electricity.
In fact, just 30% of the energy used by an air source heat pump is typically provided by electricity. The rest is generated by the environment!
This means that heat pumps generate more heat than the electricity that powers them.
So, although the price of electricity is currently higher than the cost of gas, you’ll be using a lot less of it – allowing you to keep your energy bills down.
Of course, this does depend on the relative price you pay for gas and electricity. This is sometimes called the spark gap and it differs from country to country but also between buildings as there are widely different tariffs paid.
Factors affecting the cost of running an air source heat pump
As we’ve touched upon already, there are lots of different factors that can affect how much a heat pump costs to run.
After all, no two buildings are the same. Commercial heat pump systems must be designed around the individual needs of a building and its occupants in order to ensure it’s working as efficiently as possible.
Here are some of the main considerations that come into play when calculating heat pump running costs.
Efficiency rating
Different heat pumps have different efficiency ratings.
This is measured by the heat pump’s Coefficient of Performance (COP), which is the ratio of heating capacity and total power input.
For instance, a COP of 2.5 indicates that, at a steady state, you generate 2.5 kW of heating capacity by using 1 kW of electric power.
At Clade, we typically see COPs between 3 and 4 in our heat pumps. Sometimes, they can be even higher depending on the conditions.
However, COPs are a moment in time and specific to the conditions at the time. On the other hand, Seasonal Coefficient of Performance (SCOP) is a measure of performance over a year. More on this below.
Ambient temperatures
The cooler the temperatures outside, the less efficiently your heat pump will operate.
This is because the compressor inside your heat pump will need to work harder to achieve the required flow temperature.
In this way, your heat pump’s COP can decrease in cold weather – leading to higher running costs.
Outlet temperature
As a rule of thumb, the higher the outlet temperature of the heat pump, the more work the compressor inside the heat pump has to do to achieve the required temperature. This pushes up your energy bills.
That’s why heat pumps usually perform best when they’re paired with larger radiators or underfloor heating, which require a lower inlet temperature.
However, there are exceptions. For instance, our CO2 heat pumps are actually more efficient at higher output temperatures because of the unique thermodynamic properties of CO2.
Heat pump size
It’s really important that your heat pump is correctly sized for your building’s needs.
A heat pump that’s too small will mean that your unit runs constantly as it fruitlessly tries to reach your temperature requirements – increasing your energy bills.
Meanwhile, a heat pump that’s too big will run short cycles that risk leading to costly repairs and early replacement.
Heating requirements
The way that you use your heat pump can affect your COP and therefore how much you pay for your heating.
For instance, do you need a heat pump just for space heating, or for space heating and domestic hot water? Is there a big heating demand at a set time of day?
These factors will have a bearing on what kind of heat pump system you need and how hard your heat pump has to work to provide the desired heat output.
Refrigerant
Heat pumps rely on a refrigerant to transfer heat from one place to another.
However, there are lots of different refrigerants – and your choice of refrigerant gas can affect your heat pump’s overall efficiency.
Refrigerants are largely split into two groups: synthetic (mostly F-gases) and natural.
Natural refrigerants tend to be more efficient in heat pumps as they have no glide (a thermodynamic behaviour found in some synthetic refrigerants). Plus, they’re vastly better for the environment, making them a no-brainer!
Energy prices
Although there’s an energy price cap in place for domestic customers, there’s no business energy price cap.
That means energy prices can vary widely between different energy providers and businesses. Which makes it much more difficult to calculate how much you can expect to pay to run a commercial heat pump.
That said, the electrification of heat does open up the opportunity to make use of grid flexibility – using energy at times of the day where it’s cheaper. Businesses that can take advantage of this could cut their energy bills drastically.
Energy source
Most businesses will get the electricity they use to power their heat pump from the National Grid.
But there’s also the option to power your heat pump using renewable energy sources – such as wind or solar power.
As well as being even better for the environment, it’s also a valuable opportunity to power your heat pump completely for free!
Maintenance
Regularly servicing your heat pump will help you to keep it in optimal condition and maintain its efficiency.
In this way, proper heat pump maintenance is key to keeping your energy bills low.
It can even prolong the life of your heat pump system and stave off replacement costs for as long as possible.
Calculating your heat pump running costs
To calculate roughly how much your heat pump might cost to run per kWh, you’ll need to take into account its Seasonal Coefficient of Performance (SCOP) and your energy prices.
Here are the steps involved.
1. What’s the SCOP?
Your heat pump’s SCOP is a measure of your heat pump’s efficiency, averaged out across the year.
It takes into account the fact that external temperatures can affect a heat pump’s efficiency, by summing up the heat that is generated per year and dividing it by the total electric energy use.
For air source heat pumps, this is calculated by dividing the total ambient temperature range into sub-intervals and defining the duration of each.
Heat pumps should generally be expected to generate SCOPs of 2.5 or higher.
This means that, on average, your heat pump will generate 2.5 kW of heating capacity by using 1 kW of electric power. Here, we assume that the heat pump is driven by an electric motor, which is usually the case.
2. What do you pay for electricity?
Now you have a better idea of how much electric power you can expect to use to generate your heating requirements, you’ll need to consider energy prices.
As we touched upon already, there’s no business energy price cap, so costs per kWh can vary widely.
However, to give you a rough idea of how things might look, let’s use the energy price cap for domestic customers.
For the period beginning the 1st of January 2025, this is 24.86 pence per kWh (plus a 60.97 pence daily standing charge).
3. How much does your heat pump cost to run?
Using the (very rough!) SCOP and energy prices outlined above, we can calculate a ballpark heat pump running cost.
A SCOP of 2.5 means that, for every £1 you spend, you’ll get £2.50 back
With that in mind, we have to adjust the estimated 24.86 pence per kWh to take into account the SCOP of 2.5 (250% efficiency!).
This brings us to 9.94 pence per kWh.
Remember though, 2.5 is the minimum SCOP expected. Heat pumps with higher efficiency ratings or that operate in warmer climates could lower this figure significantly!
Heat pump maintenance costs
As well as running costs, you’ll need to factor in maintenance when you’re calculating the average cost of a heat pump
Luckily, heat pumps have a robust design with minimal moving parts. That means they need very little maintenance compared to traditional gas boilers.
However, investing in a yearly service is key to keeping your heat pump in the best condition possible and therefore lowering your running costs in the long term.
The cost of heat pump servicing can vary depending on whether you opt for one-off servicing or a yearly package – as well as factors like the size of your heat pump system.
At Clade, we also offer after sales support packages that include yearly servicing, 24/7 service engineering support, access to Clade’s technical helpdesk, and commissioning engineer attendance.
In this way, we can be there to offer maintenance, support, and software upgrades throughout your system’s lifecycle.
Get a quote for your bespoke commercial heat pump system
At Clade, our team of expert engineers has more than 35 years of experience working with heat pumps and refrigeration equipment.
So, we know what we’re doing when it comes to designing, manufacturing, installing and maintaining efficient commercial heat pump systems that will keep your running costs as low as possible.
Plus, all our heat pumps use natural refrigerants and we’re a certified B Corp. That means that, when you work with us, you know you’re having a positive impact on the world around you.
Simply get in touch to start the ball rolling and have our engineers scope out your project.