Octopus Cosy Cooler add-on is expected to cost £500 to £600

Octopus Energy has developed the Cosy Cooler, an add-on that uses its heat pumps and radiator pipework to cool rooms. The company has begun trials in homes and offices in the UK and is seeking more testers.

The unit is 72cm tall, 43cm wide and 35cm deep. It connects to existing radiator pipes and a heat pump, and takes about three hours to install, according to TechRadar. Octopus says no major building work is needed. The system cools water flowing through the radiators and uses a heat exchanger to cool indoor air before circulating it back into the room.

One unit can cool one room. Octopus says users can run two to three units in different rooms, but multiple units require a higher-tier Cosy heat pump. The company offers three models: Cosy 6, Cosy 9 and Cosy 12.

Octopus expects to sell the coolers for £500 to £600 and is aiming to make them available to customers next summer. The units are currently prototypes, and prospective users can apply to take part in a trial. They are not standalone air conditioners: they require an existing Cosy heat pump.

TechRadar reports that Octopus puts the cost of a full air-conditioning system at £2,000 or more. Octopus CEO and founder Greg Jackson said British homes need to handle cold winters and increasingly hot summers. He also credited the Boiler Upgrade Scheme with helping the industry invest and reduce costs.