Radiators have been gifted with their very own “tea cosy” insulators, thanks to an innovative-yet-simple solution from an energy startup firm based at Columbia University in New York.

Across the world, millions face the same problem – that radiators in a large apartment building can be far too hot or cold for the day to day weather because the landlord has to heat the entire building with just one thermostat.

The problem is greatest in buildings warmed by radiators powered by steam heating that circulates piping network centred on the boiler. It has been tackled by the Columbia University startup Radiator Labs, which recently won the $200,000 MIT Clean Energy Prize for its insulation system for individual radiators – with a cover fitting over an individual radiator like a tea cosy.

The difference is that this tea cosy has a temperature monitor and a fan inside it, which switches on when the room gets too cold, releasing the radiator’s heat and warming the area. When the room is hot enough, the sensor switches off the fan and the radiator cover traps any extra heat.