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.



45/2 BBU Efficiency

SAP seasonal efficiency


Rating band

Band G


ManufacturerGlow-worm Boilers
Model45/2 BBU
Fuel TypeGas
Flue TypeOpen
FanNo Fan
Output (kW)9.5 - 13.8
Boiler ID44 315 39
Manufactured From/To1997 - 2002


The Glow-worm 45/2 BBU is a 'G' rated boiler with a very poor efficiency of 68.4%.

The 45/2 BBU is a Non-Condensing Conventional boiler with a maximum power output of 13.8kw that uses Gas as its fuel source.

Being a 'G' rated boiler it would be worthwhile replacing it with a higher efficiency 'A' rated boiler.


Similar Glow-worm Boilers to the 45/2 BBU
(Non-Condensing Gas Conventional)

Results ordered by efficiency. Some models may be obsolete.

Glow-worm 30 si

79.7% Efficient

Glow-worm Ultimate 30FF

79.7% Efficient

Most Efficient Conventional Gas Boilers

Baxi Solo 15 HE A

91.3% Efficient

Main 15 HE A

91.3% Efficient

Potterton Promax SL 15

91.3% Efficient

Potterton Gold H 15

91.3% Efficient