GB 20665 Minimum allowable values of energy efficiency and energy efficiency grades for domestic gas instantaneous water heaters and gas fired heating and hot water combi-boilers

Last updated: 1 April 2019

Applies to instantaneous water heaters and heating and hot water combi-boilers which use gas as source and whose heat load is equal to or smaller than 70kW

End uses covered
  • Building end-uses
  • Building systems
  • Water heating