The Co-operative has become the first supermarket chain in the UK to put its chilled products behind closed doors.
The company has tried the idea at 100 of its stores, and found that, by displaying milk, cheese and similar products behind glass doors, it has so far saved £50 million on its energy bills.
Of course, customers can still open the fridge doors when they want to buy something – but other supermarkets are hesitating to follow the Co-op's lead for fear of losing sales, The Guardian reported.
However, it added: "If all the UK's supermarkets put doors on their fridges, the electricity saved would be roughly double the output of the giant Drax coal-fired power station in Yorkshire, Europe's second largest."
Dave Roberts, the Co-op's director of property, explained, however, that the company got around the problem of customers feeling that they couldn't access the goods as easily by installing LED lights around the fridge doors: "Customers said it brought the product to life," he said, adding: "In no places where we have put doors on fridges have sales gone down."
Refrigeration accounts for half of all the power consumed by Co-op stores and energy bills were the chain's second biggest cost after staff, Roberts told The Guardian.
The new fridges also run on smaller motors, which break down less in hot weather, he added.