British startup Nusku has presented a prototype of a fully integrated air heating system that combines a heat pump, a hot water cylinder and a control system in a single outdoor unit.
The novelty of the all-in-one system lies in its integrated, pre-packaged design. Conventional heat pump systems typically require a separate outdoor unit, an indoor hot water cylinder and additional installation equipment. Nusku’s system, on the other hand, combines all essential components, including the heat pump and a compact hot water boiler, in one outdoor unit.
“We know that many people are put off by having to find space in their home for a water cylinder because it means losing valuable storage space,” Nusku CEO Russell Murchie said in a statement. “The prospect of installing new radiators and a lengthy and disruptive installation process is also a major barrier, along with the potential noise generated by the heat pump and the misconceptions about cost and performance. Our design overcomes all these issues, making it faster and easier for people to replace their gas boilers and switch to renewable energy with a heat pump that meets all their needs.”
According to a document published by the UK Department for Energy Security and Net Zero, the system relies on a closed-loop controller that can significantly reduce heat pump cycling.
“Nusku’s closed-loop controller reduced energy cycles by more than 25%, including defrost cycles, over a heating season compared to weather compensation, improving operational efficiency and extending compressor life,” the document said. “Modelling of a full heating season shows that the Nusku heat pump can provide equivalent comfort levels to a gas boiler, at up to 33% lower costs using the OVO Heat Pump Plus tariff, or an 8% saving using a time-of-use tariff and some pre-heating.”
The OVO Heat Pump Plus tariff is an add-on that effectively reduces the cost of electricity consumed by a heat pump by offering UK customers a monthly bill credit. Instead of changing usage patterns, customers pay their standard rate in advance and then receive a discount based on heat pump consumption, making heating costs more predictable and lower.
The system uses an integrated hot water cylinder designed to provide 180 liters of hot water at 40 C. This is achieved by storing water at a higher temperature and mixing it with cold water to achieve the required output volume.
The Nusku system is currently evolving from prototype to pre-commercial phase and is at Technology Readiness Level (TRL) 7–8. TRL is a scale used to measure the maturity of a technology, ranging from 1 (observed basic principles) to 9 (fully commercial, proven systems).
The system is currently undergoing validation, including independent testing at the University of Salford’s Energy House Labs. So far it has been shown to deliver a supply temperature of 65°C, can be installed in one day and offers comparable comfort and cost levels to gas boilers.
“Prototype systems are now being trialled in homes in Bristol, with wider trials planned in other UK cities ahead of a commercial launch next year,” the company said, without giving further technical details.
To develop the system, Nusku secured almost GBP 1 million ($1.35 million) in funding in April 2024, including a £727,000 government grant. a workshop and office space in Future Space – the innovation center of the University of the West of England.
