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.



100EC Efficiency

SAP seasonal efficiency


Rating band

Band D


ManufacturerProtherm Boilers
Fuel TypeGas
Flue TypeRoom-Sealed
FanFan Assisted
Output (kW)27.4 - 27.4
Boiler IDGC 47-920-33
Manufactured From/To2000 - current


The Protherm 100EC is a 'D' rated boiler with an efficiency of 79.3%.

The 100EC is a Non-Condensing Combi boiler with a maximum power output of 27.4kw that uses Gas as its fuel source.

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


Similar Protherm Boilers to the 100EC
(Non-Condensing Gas Combi)

Results ordered by efficiency. Some models may be obsolete.

Protherm 80 EC

78.7% Efficient

Protherm 80 E

78.7% Efficient

Most Efficient Combi Gas Boilers

Alpha CD50

91.2% Efficient