Listing of current British Gas combi boilers listed in declining SEDBUK rating order.

British Gas: RD : 532i Combi
gas : combi : condensing : wall mounted
Power Rating: (32.5 - 32.5 kW)
SEDBUK efficiency 90.3%

British Gas: RD : 537i Combi
gas : combi : condensing : wall mounted
Power Rating: (37.5 - 37.5 kW)
SEDBUK efficiency 90.3%

British Gas: RD : 532 Combi
gas : combi : condensing : wall mounted
Power Rating: (32.5 - 32.5 kW)
SEDBUK efficiency 90.3%

British Gas: 532 :
gas : combi : condensing : wall mounted
Power Rating: (30 - 30 kW)
SEDBUK efficiency 90.2%

British Gas: 537 :
gas : combi : condensing : wall mounted
Power Rating: (30.0 - 30.0 kW)
SEDBUK efficiency 90.2%

British Gas: 542 :
gas : combi : condensing : wall mounted
Power Rating: (30 - 30 kW)
SEDBUK efficiency 90.2%

British Gas: 537/I :
gas : combi : condensing : wall mounted
Power Rating: (30.0 - 30.0 kW)
SEDBUK efficiency 90.2%

British Gas: 532/I :
gas : combi : condensing : wall mounted
Power Rating: (30.0 - 30.0 kW)
SEDBUK efficiency 90.2%

British Gas: 542/I :
gas : combi : condensing : wall mounted
Power Rating: (30.0 - 30.0 kW)
SEDBUK efficiency 90.2%

British Gas: RD : 542i Combi
gas : combi : condensing : wall mounted
Power Rating: (40.0 - 40.0 kW)
SEDBUK efficiency 90.0%

British Gas: RD628 : RSF
gas : combi : non condensing : wall mounted
Power Rating: (28 - 28 kW)
SEDBUK efficiency 78.4%

British Gas/Scottish Gas: C1 : RSF
gas : combi : non condensing : wall mounted
Power Rating: (28 - 28 kW)
SEDBUK efficiency 78.2%

This information has been collated from Manufacturers literature and the SEDBUK online database as at April 2007.

Small variations in efficiency ratings are not significant. It can be assumed that a 3% difference in rating will give a 95% confidence that the higher rated boiler is more efficient than the lower.