Hot water bottles are selling out around the UK amid the cold snap and efforts to save on soaring energy bills. John Lewis said sales were up sixfold on last year with several popular models currently out of stock online including the department store’s own-label version with a fake fur protective cover. A number of Argos hot water bottles were also sold out in many stores in London and Manchester, when the Guardian checked on Monday. The flasks, first used in the UK in the late 1800s as a step on from metal warming pans filled with hot coals, were name-checked in recent industry data as helping to deliver stronger than expected November retail sales. A spokeswoman for John Lewis said: “Hot water bottles have been in very strong demand during the cold snap. Given their current popularity, we recommend customers to purchase soon to avoid disappointment.” With Britons desperate to reduce their energy use by keeping their heating off for as long as possible or turning the temperature down, retailers have been tempting them with an array of items to help out. Lakeland, a retailer best known for its kitchen paraphernalia, has been struggling to keep up with demand for its £90 electric heated poncho while John Lewis said onesies, normally a popular Christmas gift, were already flying off the shelves with sales more than tripling in early October. While there are many cost-free ways to cut down on energy bills, such as ensuring there is a full load in the washing machine, turning off unused lights, cutting down shower times and not overfilling the kettle, some quite pricey gadgets have been selling well. Sales of air fryers, slow cookers, microwaves and electric blankets are soaring as households look for ways to reduce their power use. Slow cookers, a 1970s favourite, were the bestselling electrical item at John Lewis in October when sales of microwaves were up 40% and smart thermostats, which make it easier to control heating systems, up by a quarter. According to MoneySavingExpert, consumer champion Martin Lewis’s website, there are savings to be made by using certain technologies, although that has to be offset against the cost of purchasing the item. It costs about 3p an hour to run an electric blanket, for example, meaning the average weekly usage would add up to just £1.47, a cheaper alternative to running central heating at night.