Hybrid heat pumps

There are two main reasons an installer might suggest fitting a hybrid heat pump system: 

• Your home has a high heat demand. 
• Your current setup means replacing it with a standalone heat pump wouldn’t lower your energy bills. 

Your home’s heat demand is the amount of heat needed for heating and hot water. Heat pumps are suitable for most UK homes. But in some cases, a heat pump might not provide enough heat to keep large homes with a high heat demand at a comfortable temperature.  

Having radiators or underfloor heating help heat pumps run more efficiently, keeping your running costs down. You could also reduce your heat demand by improving your home insulation. But if you live in a large home where insulation is either impractical or too expensive, your installer may suggest a more specialist solution. 

This might include installing: 

• a hybrid heat pump 
• a high-temperature heat pump 
• a twin heat pump installation (often called a cascaded heat pump system) 

Also, if you live in a large home, it’s worth asking a qualified electrician about upgrading your electricity to a three-phase supply. This offers more power for your home and if it’s an affordable option, it improves your options for both heat pumps and electric vehicle charging. 

Your district network operator is responsible for upgrades to your supply. You can ask your installer to help you get a quote. 

Replacing your boiler with a heat pump can result in lower heating bills, but this depends on the boiler’s efficiency and the fuel you’re replacing. For example, a modern gas boiler might be cheaper to run than a heat pump. This is because electricity is still four times more expensive per unit than gas. 

Some hybrid systems have controls that automate when and how the heat pump runs based on: 

• Electricity costs. 
• Fossil fuel supply costs (mains gas, LPG or oil). 
• Time of day, if this has an impact on electricity prices. 
• Whether any solar panels are generating or exporting electricity. 

Having the hybrid system react to fuel prices should mean the boiler only turns on when it’s cheaper to run than the heat pump. This should lower your overall operating costs compared to running the boiler or heat pump on its own. 

If you’re considering a hybrid system for this, check the assumptions your installer makes when deciding when the heat pump will run vs the boiler. 

You should also review gas and electricity tariffs and compare them to what you’re paying now, and what you expect to pay in the future. Speak to your installer about the heat pump setup and ask them to explain their running cost calculations. 

The two most likely configuration options would be: 

We always recommend that you get quotes from at least three installers, including their opinion on the most suitable system for your home and needs.  

Make sure any installers are certified by the Microgeneration Certification Scheme (MCS). You can find a list of qualified heat pump engineers near you on the MCS website. 

Your installer should provide: 

• Running costs for the designed system. 
• Assumptions of heat pump efficiency, boiler efficiency and fuel prices. 

For more information, read our guide to the heat pump installation process. 

Heat pump types include air source, ground source, and air-to-air. This quiz from Nesta will help you understand which may be right for you. You can also find out more about each type of heat pump:

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