Boiler Efficiency Ratings

Compare new boilers and assess whether your current boiler would be better off being replaced

Our boiler efficiency tables provided by SEDBUK (the seasonal efficiency of domestic boilers in the UK) provide a guide of how effective your boiler is at turning fuel into heat.

You can check your boilers rating by selecting it’s make and model below. Ratings are based on the SEDBUK Rating which is an indicator of its efficiency when used within an average domestic household, it’s a great benchmark for comparing new boilers and also assessing whether your current boiler would be better off being replaced due to low efficiencies.

For new boiler installations call British Gas Boilers on 0333 230 5216 for a no-obligation quote, alternatively visit Boiler Guide to request quotes from independent local and regional heating engineers.



Greenstar Utility 18/25-OOO-GB Efficiency

SAP seasonal efficiency


Rating band

Band A


ManufacturerWorcester Boilers
ModelGreenstar Utility 18/25-OOO-GB
Fuel TypeOil
Flue TypeOpen or Room-Sealed
FanFan Assisted
Output (kW)18 - 25
Boiler ID
Manufactured From/To2005 - current


The Worcester Greenstar Utility 18/25-OOO-GB is an 'A' rated boiler which has an excellent efficiency of 92.9%.

The Greenstar Utility 18/25-OOO-GB is a Condensing Conventional boiler with a maximum power output of 25kw that uses Oil as its fuel source.

As this boiler is 'A' rated it will provide efficient heating and subsequently reduce fuel bills and carbon dioxide emissions.


Similar Worcester Boilers to the Greenstar Utility 18/25-OOO-GB
(Condensing Oil Conventional)

Results ordered by efficiency. Some models may be obsolete.

Most Efficient Conventional Oil Boilers

Grant Vortex 36

97.0% Efficient