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British / Scottish Gas RD121 Silver Gas - Boiler Efficiency Ratings

Boiler Efficiency Rating

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 0800 327 7119 for a no-obligation quote, alternatively visit Boiler Guide to request quotes from independent local and regional heating engineers.

British / Scottish Gas RD121 Silver Efficiency

SAP seasonal efficiency78.5%
Rating bandBand D


ManufacturerBritish / Scottish Gas Boilers
ModelRD121 Silver
Fuel TypeGas
Flue TypeRoom-Sealed
FanFan Assisted
Output (kW)20.5 - 20.5
Boiler IDGC No. 41 397 79
Manufactured From/To2003 - current


The British / Scottish Gas RD121 Silver is a 'D' rated boiler with an efficiency of 78.5%.

The RD121 Silver is a Non-Condensing Conventional boiler with a maximum power output of 20.5kw 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 British / Scottish Gas Boilers to the RD121 Silver
(Non-Condensing Gas Conventional)

Results ordered by efficiency. Some models may be obsolete.

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