Cotswold stovemaker Everhot Cookers is basking in the glow of a victory with the Advertising Standards Authority (ASA) after the watchdogs upheld a complaint against claims from the makers of the Aga, telling the Swedish brand that its claims were "misleading".

AGA Rangemaster Group Limited, based in Leamington Spa, published claims on the agaliving.com website about the running costs of its eR7 cooker which suggested that its model was cheaper to run than any other heat storage cast-iron range cooker, being "fully programmable for the most efficient operation".

Taking issue, Everhot, who have a factory in Dursley and are headquartered at the founding family's 13th century mill in Coaley, asked the ASA to adjudicate. The ASA's own research subsequently determined that the eR7 could cost up to twice as much to run as the equivalent Everhot cooker.

In tests where the hotplate was run on full power, the AGa eR7 emerged at 18p per hour while the Everhot 110i cost 6.6p.

Guy Goring, owner of Everhot Cookers, told Punchline-Gloucester.com: "We are delighted that the ASA has upheld our complaint against Aga's energy efficiency claims. Everhot Cookers are the most energy efficient heat storage range cookers on the market today. A fact we have always stuck by because of its importance to us as a British-built range cooker manufacturer."

He added: "Everhot is transparent with the energy efficiency of its cookers, consistently publishing running costs with all hot plates and ovens on full during the day and dropping into our automatic ECO settings overnight.

"With electricity costs in the forefront of everyone's minds, we know how important it is for customers to be able to understand and interpret running costs and easily compare cooker brands so they can make the right decision for them."

Using largely British components that include sheet metal from a Stonehouse company bought by Everhot, the maker builds its cooker by hand at the Littlecombe Business Park in Dursley, having expanded to an initial 6,400 square foot space there in 2008.

Everhot's story stems back to 1979 when founder and engineer, Guy's father Ossie Goring, (who began his career as a Lister engineer) decided to try to create a more efficient and clean stove for his wife, hooking it up to energy created from a water wheel at their ancient mill home. The company's sales of stove cookers have steadily climbed – from 600 a year in 2014 to 3,000 in 2022.

Guy added: "Our desire to conserve energy has been at the heart of our business philosophy ever since it inspired the invention of the first ever Everhot over 40 years ago. Our unique trickle feed design optimises the use of renewable power sources and enables our cookers to be simply plugged into 13amp sockets. Sustainability remains deeply embedded in our DNA and we never stop innovating to improve our cookers' efficiency."

● The cheapest Everhot product is the 600mm-wide Everhot 60, from £7,095 including VAT at 20%.