Cascaded heat pumps

A cascaded heat pump system allows more than one heat pump unit to work together to meet a property’s heating and hot water needs.

Separate heat pump units can be designed to operate at the same time for different tasks (eg one for heating, another for hot water). They can also share the property’s heating and hot water demand between them.

Cascaded heat pumps only have a single control panel to manage the installation. When it’s warmer outside, only one heat pump needs to operate to heat the property efficiently. As it gets colder, the second unit may be needed to supply either hot water or extra help with heating.

By having only one control system, heat and hot water requirements can be managed or split across two heat pumps. This helps them operate as efficiently as possible. Sometimes this might mean one is providing heating while the other provides hot water. At other times, both might only provide heating or one may be switched off entirely.

If you have a large house, your electricity supply might not be able to deliver all the heating energy needed via a single heat pump. Cascaded heat pumps overcome this problem and can be an ideal heating solution for larger homes.

Most houses in the UK have what is described as a ‘single phase’ electricity supply. Bigger commercial buildings have ‘three phase’ electricity supplies which allows them to use more electricity and larger heat pumps.

Single phase domestic heat pumps are generally designed to only deliver a maximum of around 12-14kW of heating power. If you live in a house with a high heat demand, a single heat pump might not be able to provide heating all year round. In this scenario, you might benefit from a cascaded heat pump system.

Looking for an installer? We recommend you choose a certified installer and system that are both accredited through the Microgeneration Certification Scheme (MCS).

Hybrid heat pumps are another possible solution for buildings with high heat demands on single phase power supplies. These use a back-up boiler or other heating source to make up any shortfall in extremely cold weather.

An experienced installer will advise on what the best solution might be for your property. There might be multiple ways to meet your heating needs, so it’s a good idea to speak to at least three installers for recommendations.

• A low carbon heating system
• Suitable for properties with high heating demands
• Able to maintain comfort during very cold weather