Boilers with a SEDBUK Band Rating of “E” have an efficiency value of between seventy-four and seventy-eight percent (74%-78%). If you have a Standard (non-condensing) GAS Boiler already installed & would like to check it’s SEDBUK SAP rating – please view the complete, full boiler list on the SEDBUK Band E (efficiency rating between 74%-78%) Boiler Ratings Page! HINT: Click the image (on the left!) to read more…