The overall rating of 79%, with maximum score in 5 out of 6 categories based on customer scores and engineers views.
For the first time, the Oil boiler range was also highly recommended.
The entire range of Greenstar gas boilers has once again come out on top in the Which? Boiler Report, having been awarded Which? Best Buy for the 6th year running.
The Greenstar range scored 5 stars for reliability, customer satisfaction and build quality as well as achieving the maximum star rating in 5 of the 6 categories.
The annual survey compared 11 brands in total, revealing Worcester to be the most reliable, with boilers remaining fault free longer than all other manufacturers.
The results were calculated from the views of 10,779 owners and for the first time a 110 Which? Trusted Trader heating engineers were surveyed, with responses included only for brands they were not incentivised to install.
A summary of the report noted that Worcester gas appliances offer: “Fantastic build quality and easy to source parts and spares.” It continues, “with extremely reliable products across the range… a Worcester, Bosch Group gas boiler is worthy of its Best Buy status.”