How efficient are heat pumps? What do SCOP and COP mean?

24 June 2024 | OVO

When looking into whether a heat pump is right for you, you’re bound to hear talk of their efficiency. You might even come across the term “SCOP” or Seasonal Coefficient of Performance. And hear claims of heat pumps being around 400% efficient. 

Here, we explore how efficient heat pumps really are – and why it’s so important. 

What’s a heat pump efficiency score?

Put simply, it tells you how much heat you get out for every kWh of electricity you put in. Putting 1 kWh into your heat pump and getting 1kW of heating out, gives a heat pump efficiency score of 100%. 

Thankfully, heat pumps are much more efficient than this. They’re renowned for generating much more heat than the electricity used to power them. 

What does COP mean?

COP, or Coefficient of Performance, describes the efficiency of your heat pump. Air source heat pumps are very efficient. For every unit of electrical energy they take from the National Grid, on average they give out about 2.8 times the amount of heat. That’s a Coefficient of Performance, or COP, of 2.8. 

So the higher a heat pump’s COP the better. Your system’s efficiency will also depend on: 

  • The heat pump you buy – so you might want to check its “maximum COP” 
  • The quality of the installation

That’s why it’s so important to make sure you use a reputable and accredited installer. They can make sure you pick the right heat pump for your home. When you get a heat pump through OVO, it’ll be installed by Heat Geek’s national network of award-winning installers. They’ve got a track record of achieving SCOPs that are around 50% more efficient than the UK average1 – so you’ll be in safe hands. 

How’s COP calculated? 

COP is calculated by dividing your energy output by the energy input. The higher the COP, the more efficient your system. 

OVO customer looking at heat pump control

What’s the difference between SCOP and COP? 

COP is useful because it can show us the efficiency of a heat pump at any given moment. But it’s a snapshot, and doesn’t tell us what a heat pump’s efficiency is over the entire heating season. 

A heat pump will have to work harder in the winter to generate more heat, so the efficiency at this time of year will be lower. SCOP, on the other hand – or Seasonal Coefficient of Performance – takes this into account. It tells us what the average COP is over an entire heating season, making it a more reliable way to judge heat pump efficiency. 

How efficient are heat pumps compared to gas boilers?

The national average for A-rated boilers is 90% efficiency. This means for every 1kWh of gas burned by the boiler, you’d get 0.9kW of heat out. In comparison, air source heat pumps have a UK average SCOP of 2.8, meaning they’re 280% efficient. A more efficient system means lower running costs, as less electricity is needed to heat your home.

Installers carrying out high quality installations are able to achieve even higher SCOPs. If you get a heat pump through OVO, it’ll be installed by our partners at Heat Geek. They achieve an average SCOP of 4.2, which can help cut your running costs even further.1

What impacts heat pump efficiency? 

The more efficient the heat pump, the less it costs to run. So if you want to keep your heating bills down, it’s a good idea to think about the following…

The quality of your heat pump installation 

A high-quality heat pump installation by an MCS-accredited installer will make a big difference to your system's efficiency. And, in turn, the cost of heating your home. 

Working with a properly trained installer who really understands your system is vital. They’ll not only design a system that’s right for your home. They’ll also be able to optimise the settings of your system to make it as efficient as possible. For example, using your heat pump’s “weather compensation” settings they can adjust your “flow temperature” in line with the weather. This means your heat source can be run at a lower temperature. And your radiators will only produce as much heat as the room needs.   

A great installer really does make all the difference. That’s why we’ve partnered with Heat Geek and their network of award-winning installers. Every engineer is highly trained, and the heat pumps they fit are around 50% more efficient than the UK average.1 A good installer will also advise you on how to prepare your home so that a heat pump can work at its best. 

One of the most common tips they’ll give you? Improve your home’s insulation.

Good insulation 

The more insulated your home, the less heat will escape. This means your heat pump can keep you cosy for longer and save you money too. Well insulated homes are also more suited to smaller heat pumps that are cheaper to buy – and run. 

If your home needs an insulation upgrade, check out the Great British Insulation Scheme. It offers handy grants towards cavity wall or loft insulation.

The right heat pump model 

When it comes to choosing a model, the modern ones are usually best. We rate those in the Vaillant aroTHERM range because their controls are superior to their older counterparts. It's these clever smart controls that allow you to tweak the pump’s performance – and maximise its efficiency. 

Again, a good installer can walk you through the models that will work best in your home.

Interested in saying goodbye to gas? Get your heat pump through OVO.

You can now get your heat pump installed through our exclusive partnership with Heat Geek. With a heat pump, you can save up to £150 a year on your heating bills compared to a gas boiler.2 You’ll also unlock our free add-on, Heat Pump Plus, which gives you a cheaper electricity rate to power your heat pump for less.

Find out more and register for updates.

Sources and references:

1 Based on Heat Geek’s average SCOP of 4.2 versus the UK average SCOP of 2.8.

2 Savings of £150 are based on the following comparison: a gas boiler running at 90% efficiency (as per the national average for A-rated boilers) with an annual consumption of 11,500 kWh at 5.21p/kWh, and 77% of consumption used for heating and hot water, versus an air source heat pump with a Seasonal Coefficient of Performance (or efficiency rating) of 4 and an annual consumption of 1,992 kWh at 15p/kWh with the Heat Pump Plus add-on.