The survey asked more than 2,800 consumers who had had a gas boiler installed since 2005 to state how satisfied they were with their brand and whether they would recommend that brand to a friend. Vaillant had the highest customer satisfaction score of 83%, while sister brand Glow-worm had the third highest score of 73%. In stark contrast, the lowest brand scored 47%.

Both brands have previously won 'Best Buy' awards as a result of past boiler performance tests undertaken by Which? Vaillant received the combi boiler award for the ecoTEC Plus 824/831, due to its low NOx emissions and convenient, easy to use features, while Glow-worm received the open vent boiler award for the Ultracom 24 hxi, which scored highly for ease of installation, servicing and use.

Jim Moore, UK Managing Director for Vaillant Group, commented: "The result of this highly influential survey is fantastic news, as it shows how highly Vaillant Group products are valued by householders across the UK. It is testament to our ongoing investment in energy saving technologies and the hard work of our staff across the brands that our products are rated so highly.

“Vaillant Group has a renowned reputation for quality manufacturing across the globe. The Which? survey results further reinforce the leading position of both brands as suppliers of heating systems to customers across the UK."

Which? is highly regarded as one of the most respected and impartial consumer publications across the UK, providing householders with unbiased test reports across a wide variety of products including audio, kitchen appliances, computers and cars.

For more information on our ecoTEC plus combination boiler range please click here