Worcester’s
Greenstar condensing
boilers are at least 90%
efficient, meaning that
they turn 90% of the
fuel they use into heat.The official rating for boiler efficiency is the ‘SEDBUK’ scale. SEDBUK stands for ‘Seasonal Efficiency of a Domestic Boiler in the UK’.
Greenstar condensing
boilers achieve the
highest possible
efficiency category –
SEDBUK Band ‘A’.
What is a condensing boiler?
The term ‘condensing boiler’ refers to the fact that the boilers produce condense from time to time.
Condensing boilers use heat from exhaust gases that would normally be released into the atmosphere through the flue. To use this latent heat, the water vapour from the exhaust gas is turned into liquid condensate.
In order to make the most of the latent heat within the condensate, condensing boilers use a larger heat exchanger, or sometimes a secondary heat exchanger.
Due to this process, a condensing boiler is able to extract more heat from the fuel it uses than a standard efficiency boiler. It also means that less heat is lost through the flue gases.
What is SEDBUK?
The SEDBUK rating was
developed under the UK
Government’s ‘energy
efficiency best practice
programme’ with the
co-operation of boiler
manufacturers, including
Worcester. It provides a
basis for fair
comparison of different
models of boilers.
The SEDBUK rating is the average annual efficiency achieved in typical domestic situations. It takes into account sensible assumptions about climate, control, pattern of usage and other similar factors.
The rating is calculated from laboratory tests together with other important factors such as boiler type, fuel used, ignition type, UK climate, boiler water content and typical domestic usage patterns. So, for estimating annual fuel running costs SEDBUK is a better guide than laboratory test results alone.
The
boiler’s performance is
scored, enabling the
boiler to be placed in a
banding system using a
scale from ‘A’ to ‘G’.
‘A’ rated boilers are
the most efficient.
Condensing Boiler Regulations
Building regulations that have come into force since 1st April 2005 state that any replacement or new gas or oil boiler must be a condensing boiler. Rare exceptions can apply.









