A typical heat pump in the UK will cost between £1,500 and £2,000 a year to run. This figure is very much based on an average sized home, with reasonably good insulation and energy saving properties. But in reality the costs can vary widely – depending on what kind of home you have, the climate where you live and the heat pump you install.
Full disclosure, this article can get a bit technical and geeky. But if you can make it to the end, it should give you some idea of the likely costs in your particular set up.
As a final note, this article is about the running costs of an air source heat pump – or in other words how much your heat pump will cost you to run on a yearly basis. If you’re looking for more information about the installation costs of an air source heat pump we advise you check out our article ‘how much does an air source heat pump cost‘, which examines this in depth.
How we wrote this article
We looked at a number of research resources to make sure this article was accurate. These included:
- Government sources such as gov.uk and figures from The Boiler Upgrade Scheme and the Met Office.
- Industry sources such as MCS and The Energy Savings Trust.
- Our own experience and industry knowledge.
How an air source heat pump works
We’ve covered this elsewhere on WeLoveHeatPumps, but here’s a quick recap:
A heat pump takes heat from outside your home, compresses it to make it hotter, and then distributes it inside. A ground source heat pump takes heat from the ground outside, while an air source heat pump takes heat from the outside air.
Most heat pumps in the UK are air to water heat pumps. These types of system use the heat gathered from outside the home to heat water inside your home. This water is then used to distribute heat inside your home via radiators or underfloor heating. It can also be used for showers and baths.
In the US and some parts of continental Europe, air to air heat pumps are more popular. These types of system distribute the heat gathered from outside the home via hot air ducts inside. They are generally cheaper to install that air to water systems, but you will require a solution (such as a gas boiler) to heat your hot water.
What factors affect the running costs of an air source heat pump?
The good news is that air source heat pumps are much more efficient than traditional gas boilers. But as with anything, the running costs of an air source heat pump will come down to a few factors.
The efficiency of the heat pump
A traditional gas boiler works at an efficiency of around 90%. That means for every 10 units of (gas) energy it consumes, it outputs around 9 of those as heat for your home.
A heat pump is much more efficient than that. We normally measure the energy efficiency of an air source heat pump in something called the Coefficient of Performance (COP). This states how many units of energy it outputs for every unit it consumes. A typical air source heat pump will work to a COP of around 4. This means for every unit of electricity it uses it outputs 4 units in heat for your home.
The outside temperature
It’s no surprise to learn that the colder it is outside, the harder your heat pump will have to work to keep you toasty.
An normal air source heat pump will keep you warm right down to minus 20C – plenty enough for the UK climate. But below a certain temperature it may not be the most efficient way to heat your home. While we measure the COP at a standard temperature, in practice, engineers prefer to use something called the Seasonal Coefficient of Performance. This number describes the average COP during a heating season and is a much more reliable indicator of your heat pump’s efficiency.
The SCOP of the average air source heat pump generally ranges between 3-4. So for every unit of energy the heat pump consumes, it generates between 3 and 4 in heat.
The minimum that MCA allow for compliant heat pump installation is 2.8, while the average is 3.4.
The insulation inside your home
One of the key factors in getting a heat pump to work effectively is making sure your home retains heat. Leaky, energy inefficient homes don’t work well with heat pumps. This partly because a heat pump runs at a much lower flow temperature than a gas boiler. Because the heat output inside your home is lower, it’s vital to retain as much heat as possible.
This isn’t so much of an issue if you have a very new home. Modern building standards are very much focussed on insulation reducing energy loss. For an older home, it can be a challenge.
We’ve written about this elsewhere on the site. If you have an older home we encourage you to read more to see whether your home is suitable for a heat pump, or what you can do to rectify it.
The cost of electricity in your region
Heat pumps run on electricity. The more electricity costs in your area, the higher your bills will be.
Although heat pumps are much more efficient than gas boilers, the cost of electricity in the UK at the time of writing (Nov 24) is much higher than the cost of gas. We will look in more detail at the cost of consumption below.
The way your use your air source heat pump
This is an important factor which homeowners overlook. Many consumers, think of heat pumps like gas boilers. They set them to come on in the morning and the evening. But this is not the most efficient way to use the system.
Unlike a gas boiler, a heat pump works best when it is running continuously and providing a gentle heat to your home. The heat pump is designed to run continuously and will switch itself on and off as needed. By running your heat pump this way, you’ll not only get the more efficient performance, but it will last longer too.
Estimating your heat pump’s running costs
So far so good. Now we’ve understood the factors than can affect the running costs of a heat pump, it’s time to dive into a few figures:
Figuring our your home’s heating requirements
When estimating the running costs of an air source heat pump, we need to figure out how many units of energy we will need to heat the house in one year. We normally express this in Killowatts per hour or kWh.
We know that the average house in the UK uses around 16,000 kWhs over the course of a year in total for heating, lighting and hot water. The problem is that this is very generalised.
There are some rule of thumb calculations on the net which look at the average kWh used annually per m2 of surface area in your home. The problem with these is that they don’t really take into consideration the type of home you have and how well it retains heat. Fitting a heat pump in an old Victorian house is going to be a very different kettle of fish from a modern new build.
Looking at your home’s heat loss
To get an more accurate understanding of the annual heating requirements of your home, we first need to work how much heat your home loses. Now the gold standard of this is to have a personalised heat loss survey performed by a qualified engineer. They will look very closely at the fabric of your home, including all your doors, windows and insulation, and calculate what the heat loss is likely to be.
If you are thinking of having an air source heat pump installed we highly recommend that you do this. However if you’re looking to get a rough idea of the running costs of a heat pump we like this chart from Heat Geeks:
| Type of Property | Watts per m2 |
| Passive haus | 2-10 |
| Eco/low carbon home | 10-20 |
| Recent new build (post 2006) | 20-40 |
| Pre 2006 new build or recent renovation | 30-50 |
| Renovated properties (cavity wall insulation and +75mm loft insulation) | 40-65 |
| Victorian houses (single and double glazing, 55-75mm loft insulation) | 65-85 |
| Victorian or older, single glazed, no loft insulation | 95-110 |
| If the property is going to be on/off | add 10% |
| If intermittently heated, i.e. a holiday home | add 20% |
The heat loss is expressed at Watts per m2. The calculations behind this are a little complicated but they refer to the amount of heat energy that is lost from a surface per unit of area per unit of time. Essentially it’s how much heat is escaping through your home.
Unsurprisingly we can see that energy performance of your home deteriorates, the heat loss increases. A recent new build might only lose 20W per m2, but a Victorian Home with a mix of single and double glazing may lose 85W/m2.
So for a 145m2 new build you might be looking at a loss of 2900W (145m2 x 20W/m2). However for our old school Victorian home of the same size we would be at 12,325W (145m2 x 85W/m2)
For our next calculation it helps to divide this figure by 1,000 to get a KiloWatt number. So we have 2.9KW and 12.325KW respectively.
Estimate heating requirements based on climate
Once you’ve worked out your heat loss, the next step is to work out the average heating demand based on where you live in the country.
The Heating degree days (HDD) method is used in a lot of places, including the US, UK and the European Union. HDD expressed how many days and how many degrees the weather is below an agreed base temperature. One HDD means the temperature conditions outside the building were below the base temperature by one degree for one day. The more HDD days the more heat is required to maintain an internal temperature.
HDDs for the UK are published by the met office and vary according to where you are in the country. According to the UK Government the average number of HDD was 1,800 in 2023.
To get the total killowatt hours (kWh) required to heat our homes over the course of a year we can use the following maths:
Annual Heating Demand = Heat Loss x Heating Degree Days
So for our 145m2 new build and using the average 1,800 HDD days for the uk it’s as follows:
2.9KW x 1800 HDD = 5,200 kWh
For our Victorian house it’s:
12.325kW x 1,800HDD = 22,185kWh
Work out the running costs of your heat pump
As we’ve discussed above an air source heat pump will have a Seasonal Coefficient of Performance of between 3 and 4. So for every unit of energy the heat pump consumes it outputs between 3 and 4 times that in heat.
The MCA have stated that the average SCOP for a heat pump in the UK is 3.4. Using this figure it’s then possible to work out how much energy our heat pump will consume in the course of a year.
For our well insulated new build home the maths is as follows:
5,200 kWh ÷ 3.4 (average SCOP) = 1,530 kWh required.
For our leaky Victorian home it’s as follows:
22,185 kWh ÷ 3.4 = 6,525 kWh required
If we know the cost of a kWh in our region, we can use this to work out the potential running costs. At the time of writing (December 2024), Ofcom have capped the price of a kWh or electricity at 24.86. So if we use this figure:
The yearly cost for our new build house is:
1,530 kWh x 0.2486 = £380.36
So our new build house costs £380,36 to heat over the course of a year according to the maths
The yearly cost for our leaky Victorian home is:
6,525 kWh x 0.2486 = £1,622.17
Our Victorian house costs £1,622.17 to heat
Now, for anyone that’s had an air source heat pump, these figures might seem a little low. But we need to remember a few things:
- These figures do not include any standing charges for the meter. This will likely add a couple of hundred pounds onto your bills.
- They do not include the price of heating your hot water. We will deal with this in a separate article but for a family of 4 you can probably add on another 500 pounds or so.
So now we start to see figures which have a bit more basis in reality. Our new build house is closer to £1,000 a year whereas our Victorian house is closer to £2,4000.
We also need to caveat the figures as follows:
- The figures assume that the heat pump is running full time to offset the heat loss of the building.
- COP values are not constant and will vary on how the heat pump is installed.
What is the average running cost of running a heat pump in the UK?
According to the Energy Saving Trust, the average cost of running a heat pump in the UK is 1,540 per year. So this would seem to tally in quite nicely with our own calculations.
As we always say, the key to getting your heat pump to run effectively and to reduce your energy bills is to make sure your home is well insulated. We’ve plenty of information about this elsewhere on WeLoveHeatPumps.com. This is really key to making sure your heat pump installation is a success.
Tim Bichara. Tim is a tech and property entrepreneur who is passionate about modern construction and energy saving technologies
