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.

British Gas: RD : 430i System
gas : regular : condensing : wall mounted
Power Rating: (29.5 – 29.5 kW)
SEDBUK efficiency 90.7%

British Gas: RD : 428 System
gas : regular : condensing : wall mounted
Power Rating: (27.7 – 27.7 kW)
SEDBUK efficiency 90.7%

British Gas: 430/I :
gas : regular : condensing : wall mounted
Power Rating: (30.0 – 30.0 kW)
SEDBUK efficiency 90.3%

British Gas: 430 :
gas : regular : condensing : wall mounted
Power Rating: (30 – 30 kW)
SEDBUK efficiency 90.3%

British / Scottish Gas: RD2 470 :
gas : regular : non condensing : floor mounted
Power Rating: 20.5 kW SEDBUK efficiency 79.9%

British / Scottish Gas: RD2 480 :
gas : regular : non condensing : floor mounted
Power Rating: 23.4 kW SEDBUK efficiency 79.7%

British / Scottish Gas: RD115 Silver :
gas : regular : non condensing : wall mounted
Power Rating: 14.7 kW SEDBUK efficiency 79.6%

British / Scottish Gas: RD115 :
gas : regular : non condensing : wall mounted
Power Rating: 14.7 kW SEDBUK efficiency 79.6%

British / Scottish Gas: RD109 :
gas : regular : non condensing : wall mounted
Power Rating: 8.8 kW SEDBUK efficiency 79.4%

British / Scottish Gas: RD109 Silver :
gas : regular : non condensing : wall mounted
Power Rating: 8.8 kW SEDBUK efficiency 79.4%

British / Scottish Gas: RD2 460 :
gas : regular : non condensing : floor mounted
Power Rating: 17.6 kW SEDBUK efficiency 79.2%

British / Scottish Gas: RD2 450 :
gas : regular : non condensing : floor mounted
Power Rating: 14.7 kW SEDBUK efficiency 79.0%

British / Scottish Gas: RD2 4100 :
gas : regular : non condensing : floor mounted
Power Rating: 29.3 kW SEDBUK efficiency 78.9%

British / Scottish Gas: RD112 Silver :
gas : regular : non condensing : wall mounted
Power Rating: 11.7 kW SEDBUK efficiency 78.6%

British / Scottish Gas: RD112 :
gas : regular : non condensing : wall mounted
Power Rating: 11.7 kW SEDBUK efficiency 78.6%

British / Scottish Gas: RD121 :
gas : regular : non condensing : wall mounted
Power Rating: 20.5 kW SEDBUK efficiency 78.5%

British / Scottish Gas: RD121 Silver :
gas : regular : non condensing : wall mounted
Power Rating: 20.5 kW SEDBUK efficiency 78.5%

British / Scottish Gas: RD2 4125 :
gas : regular : non condensing : floor mounted
Power Rating: 36.6 kW SEDBUK efficiency 78.5%

British / Scottish Gas: RD2 440 :
gas : regular : non condensing : floor mounted
Power Rating: 11.7 kW SEDBUK efficiency 78.3%

British / Scottish Gas: RD118 Silver :
gas : regular : non condensing : wall mounted
Power Rating: 17.6 kW SEDBUK efficiency 78.3%

British / Scottish Gas: RD118 :
gas : regular : non condensing : wall mounted
Power Rating: 17.6 kW SEDBUK efficiency 78.3%

British / Scottish Gas: RD124 :
gas : regular : non condensing : wall mounted
Power Rating: 23.4 kW SEDBUK efficiency 78.1%

British / Scottish Gas: RD124 Silver :
gas : regular : non condensing : wall mounted
Power Rating: 23.4 kW SEDBUK efficiency 78.1%

British / Scottish Gas: RD130 Silver :
gas : regular : non condensing : wall mounted
Power Rating: 29.3 kW SEDBUK efficiency 78.0%

British / Scottish Gas: RD130 :
gas : regular : non condensing : wall mounted
Power Rating: 29.3 kW SEDBUK efficiency 78.0%

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.

A condensing boiler is a finance saving innovative boiler that contains an extra heat exchanger to enable the hot waste gases transfer much of their inherent heat to start to heat the water in the boiler system. Once running at high efficiency, the water vapour produced in the combustion action distills back into water releasing the latent heat of vaporisation.

A result will be this liquid, refered to as condensate, often acidic, required to be piped outside to a drain or water drain. The boiler is required to be mounted on a wall and the waste fumes will travel through the flue. Hot water is supplied by a small-scale recepticle tank to facilitate rapid hot water availability.

What size of boiler should I purchase?

You should bear in mind that when first fitted central heating engineers frequently installed boilers that had a higher output than strictly necessary.. Whilst this meant that there was never the chance of the boiler falling short on its requirements, irregardless of the winter weather, it also meant that they were only using a piece of their heat generation capabilities, and so functioning under their configured optimal efficiency. If you have insulated your household since the present boiler was fitted in your house, you will likely find that you will need a humbler boiler than before.

Make sure you get advice from a CORGI installer before purchasing your next boiler

Do I need to fit oversize radiators with condensing boilers??

The main driver for smaller fuel consumption from a condensing boiler results from having a larger heat exchanger. Bigger radiators would allow lower return temperatures, and so enable greater energy efficiency, but the extra benefit has not been regarded as cost effective, as you need to remember that that the system is is only using a small part of its overall capacity for the bulk of the heating season. Whilst this affirmation is correct householders would plausibly accept this in smaller properties.

The process we have talked over was contained in the reference document for the SEDBUK project, and assessed whether there needed to be new conditions for condensing boilers. The decision was that no new recommendations were expected, and the test results forall the boiler types use the same SEDBUK formula.

A condensing boiler is a high efficiency innovative boiler that incorporates an extra heat exchanger so that the hot waste air transfer a percentage of their inherent heat to start to heat the cold water input. Once functioning at a good efficiency, the water steam developed in the burning process distills back into liquid form liberating the latent heat of vaporisation.

A consequence results in this water, called condensate, typically acidic, will need to be piped outside to a drain or water drain. The boiler will have to be mounted to a wall and the waste gases will travel through the flue. Hot water is initialy served by a little recepticle tank to enable speedy hot water availability.

What size of boiler should I get?

In earlier days boiler installers filled bigger boilers than were needed. Whilst this meant that there was never the chance of the boiler being unable to render sufficient hot water, even in the coldest wintertimes, it also meant that they were mainly working at a part load, and so functioning in an ineffective way. If you have fitted additional loft or cavity wall insulating material since the previous boiler was installed, it is highly likely that you will be recommended to install a smaller boiler than before.

We advocate looking for professional advice from a CORGI recorded fitter before selecting an appropriate replacement boiler.

Do the radiators need to be oversized with a condensing boiler?

The underlying reason for this improved efficiency from a condensing boiler is because it holds a bigger heat exchanger. Larger radiators would result in cooler return water temperatures, and so enable greater energy efficiency, but the further saving is not shown to be cost effective, as you need to remember that that the system is considerably under-loaded for the majority of the heating season. That in all probability remains true, though the smaller heating requirement for new build may well mean that householders would now allow over-sized radiators more willingly.

These consequences were counted during the SEDBUK project, and assessed whether there required to be new conditions for condensing boilers. The result was that no new recommendations were required, and the test results forall the boiler types use the same SEDBUK calculation.

A condensing boiler is a efficient advanced boiler that integrates an additional heat exchanger to enable the hot exhaust gases transfer most of their heat to pre warm the mains water to be heated. When working at maximum efficiency, the water steam developed in the combustion process turns revert back into liquid form relinquishing the latent heat of vaporisation.

A consequence is that this water, refered to as condensate, most times acidic, will need to be piped outside to a drain or soakaway. The boiler will have to be mounted on a wall and the waste fumes will rise through the flue. Hot water is supplied by a small-scale recepticle tank to facilitate rapid hot water accessibility.

Can you suggest on the right boiler size?

You should keep in mind that when first fitted central heating engineers frequently put in boilers that had a higher output than purely necessary.. Whilst this meant that there was never the chance of the boiler failing to meet the demand for heat, even in the coldest winters, it also meant that they were only employing a piece of their heat generation capabilities, and so functioning below their maximum efficiency. If you have installed additional loft or cavity wall insulation since the last boiler was fitted, it could well be that you will need a humbler boiler than the current one.

Before you purchase a new boiler we advocate you get advice from a CORGI registered fitter.

Do I need to fit oversize radiators with condensing boilers??

The main driver for smaller fuel use from a condensing boiler results from having a bigger heat exchanger. Larger radiators would result in cooler return water temperatures, and so result in even better energy performance, but the additional economies suffer from diminishing returns, as you should consider the fact that that the system is is only using a small part of its total capacity for the main heating months. Whilst this affirmation is correct homeowners would probably accept this in smaller properties.

The SEDBUK initiative considered these subjects, and evaluated whether there required to be new considerations for condensing boilers. The conclusion was that they need not, and the test results for both cases use the same SEDBUK computation.

A condensing boiler is a high efficiency modern boiler that incorporates an additional heat exchanger in order that the red-hot waste gases transfer much of their heat to pre warm the water in the boiler system. When running at a good efficiency, the water steam produced in the burning process turns revert back into water loosing the latent heat of vaporisation.

A consequence is that this liquid, called condensate, most times acidic, needs to be piped outside to a drain or soak away. The boiler should be fitted against a wall and the output fumes will pass through the flue. Hot water is initialy served by a small recepticle tank to enable convenient and rapid hot water availability.

Can you advise on the right boiler size?

It was a past practice to install outsize boilers. Whilst this ensured that there was no possibility of the boiler being unable to furnish sufficient hot water, even in the coldest winters, it also meant that they were only employing a part of their heat generation capabilities, and so running in an ineffective mode. If you have improved the energy efficiency of your household since the last boiler was fitted, it could well be that you will be commended to install a smaller boiler than before.

We advocate looking for professional advice from a CORGI registered installer before selecting a suitable substitute boiler.

Do I need to set up outsize radiators with condensing boilers??

The underlying reason for this amended efficiency from a condensing boiler is because it comprises a bigger heat exchanger. Bigger radiators would result in cooler return water temperatures, and so result in even better energy performance, but the extra economies suffer from falling returns, as you should count the fact that that the system is running at very low capacity for the majority of the heating season. That in all probability remains true, though the reduced heating requirement for new build may well mean that homeowners would now allow over-sized radiators more willingly.

The SEDBUK project looked at this, during which it was considered whether condensing boilers required to be treated differently from others. The outcome was that no new recommendations were required, and the test results forall the boiler types share the same SEDBUK computation.

Grant: Vortex : Outdoor Condensing Combi 36
oil : combi : condensing : floor mounted
Power rating 36 kW
SEDBUK efficiency 94.2%

Grant: Vortex Condensing : Combi 36
oil : combi : condensing : floor mounted
Power rating 36 kW
SEDBUK efficiency 94.2%

Grant: Vortex : Outdoor Condensing Combi 26
oil : combi : condensing : floor mounted
Power rating 26 kW
SEDBUK efficiency 92.2%

Grant: Vortex Condensing : Combi 26
oil : combi : condensing : floor mounted
Power rating 26 kW
SEDBUK efficiency 92.2%

Firebird: Combipac C20 :
oil : combi : condensing : floor mounted
Power rating (15 – 20 kW)
SEDBUK efficiency 90.7%

Firebird: Combi C20 :
oil : combi : condensing : floor mounted
Power rating (15 – 20 kW)
SEDBUK efficiency 90.7%

Firebird: Combipac C26 :
oil : combi : condensing : floor mounted
Power rating (20 – 26 kW)
SEDBUK efficiency 90.6%

Firebird: Combi C26 :
oil : combi : condensing : floor mounted
Power rating (20 – 26 kW)
SEDBUK efficiency 90.6%

Worcester: Greenstar Heatslave External : 25/32
oil : combi : condensing : floor mounted
Power rating (25 – 32 kW)
SEDBUK efficiency 90.3%

Worcester Greenstar: Heatslave : 25/32
oil : combi : condensing : floor mounted
Power rating (25 – 32 kW)
SEDBUK efficiency 90.3%

Firebird: Combipac C35 :
oil : combi : condensing : floor mounted
Power rating (26 – 35 kW)
SEDBUK efficiency 90.3%

Firebird: Combi C35 :
oil : combi : condensing : floor mounted
Power rating (26 – 35 kW)
SEDBUK efficiency 90.3%

Worcester: Greenstar Heatslave External : 12/18
oil : combi : condensing : floor mounted
Power rating (12 – 18 kW)
SEDBUK efficiency 90.2%

Worcester Greenstar: Heatslave : 12/18
oil : combi : condensing : floor mounted
Power rating (12 – 18 kW)
SEDBUK efficiency 90.2%

Grant: Vortex Outdoor : Combi 21
oil : combi : condensing : floor mounted
Power rating 21 kW
SEDBUK efficiency 90.2%

Grant: Vortex Condensing : Combi 21
oil : combi : condensing : floor mounted
Power rating 21 kW
SEDBUK efficiency 90.2%

Mistral: CC 26/40 plus contract :
oil : combi : condensing : floor mounted
Power rating (35 – 40 kW)
SEDBUK efficiency 90.2%

Mistral: CC3 26/35 plus :
oil : combi : condensing : floor mounted
Power rating (26 – 35 kW)
SEDBUK efficiency 90.2%

Mistral: CODC 26/40 plus contract :
oil : combi : condensing : floor mounted
Power rating (26 – 40 kW)
SEDBUK efficiency 90.2%

Mistral: CODC4 35/40 plus :
oil : combi : condensing : floor mounted
Power rating (35 – 40 kW)
SEDBUK efficiency 90.2%

Mistral: CC4 35/40 plus :
oil : combi : condensing : floor mounted
Power rating (35 – 40 kW)
SEDBUK efficiency 90.2%

Mistral: CC4 35/40 Std :
oil : combi : condensing : floor mounted
Power rating (35 – 40 kW)
SEDBUK efficiency 90.2%

Mistral: CODC3 26/35 Std :
oil : combi : condensing : floor mounted
Power rating (26 – 35 kW)
SEDBUK efficiency 90.2%

Mistral: CC3 26/35 Std :
oil : combi : condensing : floor mounted
Power rating (26 – 35 kW)
SEDBUK efficiency 90.2%

Mistral: CODC 26/40 Std Contract :
oil : combi : condensing : floor mounted
Power rating (26.4 – 40 kW)
SEDBUK efficiency 90.2%

Mistral: CC 26/40 Std Contract :
oil : combi : condensing : floor mounted
Power rating (26 – 40 kW)
SEDBUK efficiency 90.2%

Mistral: CODC3 26/35 plus :
oil : combi : condensing : floor mounted
Power rating (35 – 40 kW)
SEDBUK efficiency 90.2%

Mistral: CODC4 35/40 Std :
oil : combi : condensing : floor mounted
Power rating (35 – 40 kW)
SEDBUK efficiency 90.2%

Worcester: Greenstar Heatslave : 18/25-OSO-GB
oil : combi : condensing : floor mounted
Power rating (18 – 25 kW)
SEDBUK efficiency 90.1%

Worcester: Greenstar Heatslave External : 18/25
oil : combi : condensing : floor mounted
Power rating (18 – 25 kW)
SEDBUK efficiency 90.1%

Mistral: CODC 15/26 Plus Contract :
oil : combi : condensing : floor mounted
Power rating (15.0 – 26.4 kW)
SEDBUK efficiency 90.0%

Mistral: CODC2 20/26 Plus :
oil : combi : condensing : floor mounted
Power rating (20.0 – 26.4 kW)
SEDBUK efficiency 90.0%

Mistral: CODC1 15/20 Plus :
oil : combi : condensing : floor mounted
Power rating (15.0 – 20.5 kW)
SEDBUK efficiency 90.0%

Mistral: CC 15/26 Plus Contract :
oil : combi : condensing : floor mounted
Power rating (15 – 26.4 kW)
SEDBUK efficiency 90.0%

Mistral: CC1 15/20 Std :
oil : combi : condensing : floor mounted
Power rating (15 – 20.5 kW)
SEDBUK efficiency 90.0%

Mistral: CODC2 20/26 Std :
oil : combi : condensing : floor mounted
Power rating (20.0 – 26.4 kW)
SEDBUK efficiency 90.0%

Mistral: CODC 15/26 Std Contract :
oil : combi : condensing : floor mounted
Power rating (15.0 – 26.4 kW)
SEDBUK efficiency 90.0%

Mistral: CC2 20/26 Std :
oil : combi : condensing : floor mounted
Power rating (20.5 – 26.4 kW)
SEDBUK efficiency 90.0%

Mistral: CC 15/26 Std Contract :
oil : combi : condensing : floor mounted
Power rating (15 – 26.4 kW)
SEDBUK efficiency 90.0%

Mistral: CC2 20/26 Plus :
oil : combi : condensing : floor mounted
Power rating (20.5 – 26.4 kW)
SEDBUK efficiency 90.0%

Mistral: CC1 15/20 Plus :
oil : combi : condensing : floor mounted
Power rating (15 – 20.5 kW)
SEDBUK efficiency 90.0%

Warmflow: Combi : C90HE
oil : combi : condensing : floor mounted
Power rating (21 – 26 kW)
SEDBUK efficiency 90.0%

Mistral: COD – C – 7090 : Outdoor Combi
oil : combi : condensing : floor mounted
Power rating (20.5 – 26.3 kW)
SEDBUK efficiency 89.7%

Mistral: COD – C – 5070 : Outdoor Combi
oil : combi : condensing : floor mounted
Power rating (14.6 – 20.5 kW)
SEDBUK efficiency 89.7%

45 Mistral: CC1 – 5070 : Condensing Combi
oil : combi : condensing : floor mounted
Power rating (14.6 – 20.5 kW)
SEDBUK efficiency 89.7%

Mistral: CC2 – 7090 : Condensing Combi
oil : combi : condensing : floor mounted
Power rating (20.5 – 26.3 kW)
SEDBUK efficiency 89.7%

Heating World Group: Grandee Combi Condensing External : FS 15/23
oil : combi : condensing : wall mounted
Power rating (15 – 21 kW)
SEDBUK efficiency 89.1%

Heating World Group: Grandee Combi Condensing : FS 15/23
oil : combi : condensing : wall mounted
Power rating (15 – 21 kW)
SEDBUK efficiency 89.1%

Heating World Group: Grandee Combi Condensing : W 15/22
oil : combi : condensing : wall mounted
Power rating (15 – 21 kW)
SEDBUK efficiency 89.1%

Heating World Group: Grandee Combi Condensing External : W 15/22
oil : combi : condensing : wall mounted
Power rating (15 – 21 kW)
SEDBUK efficiency 89.1%

Heating World Group: Grandee Combi Condensing : FS 23/30
oil : combi : condensing : wall mounted
Power rating (23 – 26 kW)
SEDBUK efficiency 88.6%

Heating World Group: Grandee Combi Condensing External : FS 23/30
oil : combi : condensing : wall mounted
Power rating (23 – 26 kW)
SEDBUK efficiency 88.6%

Heating World Group: Grandee Combi Condensing : W 23/28
oil : combi : condensing : wall mounted
Power rating (23 – 26 kW)
SEDBUK efficiency 88.6%

Heating World Group: Grandee Combi Condensing External : W 23/28
oil : combi : condensing : wall mounted
Power rating (23 – 26 kW)
SEDBUK efficiency 88.6%

Mistral: COD3 – C – 9012 : Outdoor Combi
oil : combi : condensing : floor mounted
Power rating (26.4 – 35.2 kW)
SEDBUK efficiency 88.6%

Mistral: CC3 – 9012 : Combi
oil : combi : condensing : floor mounted
Power rating (26.4 – 35.2 kW)
SEDBUK efficiency 88.6%

Mistral: CC4 – 1215 : Combi
oil : combi : condensing : floor mounted
Power rating (35.2 – 44 kW)
SEDBUK efficiency 88.6%

Mistral: COD4 – C – 1215 : Outdoor Combi
oil : combi : condensing : floor mounted
Power rating (35.2 – 44 kW)
SEDBUK efficiency 88.6%

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.

Ideal: istor : HE325
gas : combi : condensing : floor mounted
Power Rating: (23.4 – 23.4 kW)
SEDBUK efficiency 90.9%

Ideal: istor : HE260
gas : combi : condensing : floor mounted
Power Rating: (23.4 – 23.4 kW)
SEDBUK efficiency 90.7%

Evo: HE C22/24 : HE C 22/24
gas : combi : condensing : wall mounted
Power Rating: (23.4 – 23.4 kW)
SEDBUK efficiency 90.1%

Ideal: isar : HE35
gas : combi : condensing : wall mounted
Power Rating: (23.4 – 23.4 kW)
SEDBUK efficiency 90.1%

Ideal: Isar HE 30 : HE30
gas : combi : condensing : wall mounted
Power Rating: (25.1 – 25.1 kW)
SEDBUK efficiency 90.1%

Ideal: isar : HE30
gas : combi : condensing : wall mounted
Power Rating: (23.4 – 23.4 kW)
SEDBUK efficiency 90.1%

Ideal: isar : HE30
gas : combi : condensing : wall mounted
Power Rating: (23.4 – 23.4 kW)
SEDBUK efficiency 90.1%

Evo: HE C22/35 : HE C22/35
gas : combi : condensing : wall mounted
Power Rating: (23.4 – 23.4 kW)
SEDBUK efficiency 90.1%

Ideal: isar : HE24
gas : combi : condensing : wall mounted
Power Rating: (23.4 – 23.4 kW)
SEDBUK efficiency 90.1%

Evo: HE C22/30 : HE C22/30
gas : combi : condensing : wall mounted
Power Rating: (23.3 – 23.3 kW)
SEDBUK efficiency 90.1%

Ideal: mini : HE C24
gas : combi : condensing : wall mounted
Power Rating: (24.6 – 24.6 kW)
SEDBUK efficiency 87.7%

Ideal: mini : HE C28
gas : combi : condensing : wall mounted
Power Rating: (28.3 – 28.3 kW)
SEDBUK efficiency 87.6%

Ideal: Mini : HE C32
gas : combi : condensing : wall mounted
Power Rating: (32.2 – 32.2 kW)
SEDBUK efficiency 86.8%

Ideal: excel : HE C24
gas : combi : condensing : wall mounted
Power Rating: (23.4 – 23.4 kW)
SEDBUK efficiency 86.4%

Ideal: excel : HE C28
gas : combi : condensing : wall mounted
Power Rating: (28.0 – 28.0 kW)
SEDBUK efficiency 86.4%

Ideal: excel : HE C32
gas : combi : condensing : wall mounted
Power Rating: (32.0 – 32.0 kW)
SEDBUK efficiency 86.3%

Europa: 28 : 28 kW Combi Boiler
gas : combi : non condensing : wall mounted
Power Rating: (28 – 28 kW)
SEDBUK efficiency 79.8%

Boxer: C24 : 24kW Combi Boiler
gas : combi : non condensing : wall mounted
Power Rating: (24.3 – 24.3 kW)
SEDBUK efficiency 78.9%

Europa: 24 : 24kW Combi Boiler
gas : combi : non condensing : wall mounted
Power Rating: (24.3 – 24.3 kW)
SEDBUK efficiency 78.9%

Boxer: C28 : 28kW Combi Boiler
gas : combi : non condensing : wall mounted
Power Rating: (24.3 – 24.3 kW)
SEDBUK efficiency 78.9%

Ideal: C : 95FF
gas : combi : non condensing : wall mounted
Power Rating: (27.9 – 27.9 kW)
SEDBUK efficiency 78.5%

Ideal: C : 80FF
gas : combi : non condensing : wall mounted
Power Rating: (23.26 – 23.26 kW)
SEDBUK efficiency 78.4%

Ideal: Mini C32 : 32kW Combi Boiler
gas : combi : non condensing : wall mounted
Power Rating: (32.0 – 32.0 kW)
SEDBUK efficiency 78.3%

Ideal: Mini C28 : 28kW Combi Boiler
gas : combi : non condensing : wall mounted
Power Rating: (28 – 28 kW)
SEDBUK efficiency 78.3%

Ideal: Mini C24 : 24kW Combi Boiler
gas : combi : non condensing : wall mounted
Power Rating: (24.3 – 24.3 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.

Ideal: Icos : HE36
gas : regular : condensing : wall mounted
Power Rating: (37 – 37 kW) SEDBUK efficiency 90.7%

Ideal: Icos : HE30
gas : regular : condensing : wall mounted
Power Rating: (30.1 – 30.1 kW) SEDBUK efficiency 90.7%

Ideal: Mexico : HE 36
gas : regular : condensing : floor mounted
Power Rating: (37.0 – 37.0 kW) SEDBUK efficiency 90.7%

Ideal: icos : HE15
gas : regular : condensing : wall mounted
Power Rating: (14.6 – 14.6 kW) SEDBUK efficiency 90.4%

Ideal: Maximiser : SE 42
gas : regular : condensing : wall mounted
Power Rating: (40 – 40 kW) SEDBUK efficiency 90.4%

Ideal: Imax : W60
gas : regular : condensing : wall mounted
Power Rating: (60 – 60 kW) SEDBUK efficiency 90.4%

Ideal: icos System : HE 15
gas : regular : condensing : wall mounted
Power Rating: (14.6 – 14.6 kW) SEDBUK efficiency 90.4%

Ideal: Imax : W45
gas : regular : condensing : wall mounted
Power Rating: (45 – 45 kW) SEDBUK efficiency 90.4%

Ideal: Mexico : HE15
gas : regular : condensing : floor mounted
Power Rating: (14.6 – 14.6 kW) SEDBUK efficiency 90.4%

Ideal: Mexico : HE 30
gas : regular : condensing : floor mounted
Power Rating: (30.1 – 30.1 kW) SEDBUK efficiency 90.4%

Evo: HE 16 : HE16
gas : regular : condensing : wall mounted
Power Rating: (14.6 – 14.6 kW) SEDBUK efficiency 90.4%

Evo: HE 19 : HE19
gas : regular : condensing : wall mounted
Power Rating: (18.2 – 18.2 kW) SEDBUK efficiency 90.3%

Ideal: Mexico : HE18
gas : regular : condensing : floor mounted
Power Rating: (18.2 – 18.2 kW) SEDBUK efficiency 90.3%

Evo: HE 12 : HE 12
gas : regular : condensing : wall mounted
Power Rating: (12.7 – 12.7 kW) SEDBUK efficiency 90.3%

Ideal: icos : HE18
gas : regular : condensing : wall mounted
Power Rating: (18.2 – 18.2 kW) SEDBUK efficiency 90.3%

Ideal: Icos : HE 12
gas : regular : condensing : wall mounted
Power Rating: (12.7 – 12.7 kW) SEDBUK efficiency 90.3%

Ideal: Mexico : HE 24
gas : regular : condensing : floor mounted
Power Rating: (23.4 – 23.4 kW) SEDBUK efficiency 90.2%

Ideal: Maximiser : SE 65
gas : regular : condensing : wall mounted
Power Rating: (55.1 – 55.1 kW) SEDBUK efficiency 90.2%

Ideal: icos : HE24
gas : regular : condensing : wall mounted
Power Rating: (23.4 – 23.4 kW) SEDBUK efficiency 90.2%

Ideal: icos System : HE 24
gas : regular : condensing : wall mounted
Power Rating: (23.4 – 23.4 kW) SEDBUK efficiency 90.2%

Evo: HE 22 : HE22
gas : regular : condensing : wall mounted
Power Rating: (23.4 – 23.4 kW) SEDBUK efficiency 90.2%

Ideal: Classic : HE 18
gas : regular : condensing : wall mounted
Power Rating: (18 – 18.0 kW) SEDBUK efficiency 87.5%

Optia: HE 18 :
gas : regular : condensing : wall mounted
Power Rating: (18 – 18.0 kW) SEDBUK efficiency 87.5%

Optia: HE 12 :
gas : regular : condensing : wall mounted
Power Rating: (12 – 12.0 kW) SEDBUK efficiency 87.4%

Ideal: Classic : HE 12
gas : regular : condensing : wall mounted
Power Rating: (12 – 12.0 kW) SEDBUK efficiency 87.4%

Ideal: Classic : HE 9
gas : regular : condensing : wall mounted
Power Rating: (9 – 9.0 kW) SEDBUK efficiency 87.1%

Optia: HE 9 :
gas : regular : condensing : wall mounted
Power Rating: 9.0 kW SEDBUK efficiency 87.1%

Optia: HE 15 :
gas : regular : condensing : wall mounted
Power Rating: (15 – 15.0 kW) SEDBUK efficiency 86.4%

Ideal: Classic : HE 15
gas : regular : condensing : wall mounted
Power Rating: (15 – 15.0 kW) SEDBUK efficiency 86.4%

Ideal: Concord : CXC48
gas : regular : condensing : floor mounted
Power Rating: (48.83 – 48.83 kW) SEDBUK efficiency 85.8%

Ideal: Concord : CXC70
gas : regular : condensing : floor mounted
Power Rating: (69.84 – 69.84 kW) SEDBUK efficiency 85.5%

Ideal: Concord CXSD : 40/H
gas : regular : non condensing : floor mounted
Power Rating: (43.5 – 43.5 kW) SEDBUK efficiency 80.4%

Ideal: Concord CXS : 40/H
gas : regular : non condensing : floor mounted
Power Rating: (43.5 – 43.5 kW) SEDBUK efficiency 80.4%

Ideal: Concord CXS : 60/H
gas : regular : non condensing : floor mounted
Power Rating: (65.2 – 65.2 kW) SEDBUK efficiency 80.3%

Ideal: Concord CXSD : 60/H
gas : regular : non condensing : floor mounted
Power Rating: (65.2 – 65.2 kW) SEDBUK efficiency 80.3%

Ideal: Concord CXS : 50/H
gas : regular : non condensing : floor mounted
Power Rating: (54.3 – 54.3 kW) SEDBUK efficiency 80.1%

Ideal: Concord CXSD : 50/H
gas : regular : non condensing : floor mounted
Power Rating: (54.3 – 54.3 kW) SEDBUK efficiency 80.1%

Ideal: Classic Slimline : SE9 FF
gas : regular : non condensing : wall mounted
Power Rating: 8.8 kW SEDBUK efficiency 79.9%

Ideal: Classic : SE15 RS
gas : regular : non condensing : wall mounted
Power Rating: 14.7 kW SEDBUK efficiency 79.9%

Ideal: Concord CXA : 40/H
gas : regular : non condensing : floor mounted
Power Rating: 43.5 kW SEDBUK efficiency 79.9%

Ideal: Mexico Super : 470 FF
gas : regular : non condensing : floor mounted
Power Rating: 20.5 kW SEDBUK efficiency 79.9%

Ideal: Concord CXA : 50/H
gas : regular : non condensing : floor mounted
Power Rating: 54.3 kW SEDBUK efficiency 79.9%

Ideal: Classic Slimline : SE15 FF
gas : regular : non condensing : wall mounted
Power Rating: 14.7 kW SEDBUK efficiency 79.9%

Ideal: Concord CXA : 60/H
gas : regular : non condensing : floor mounted
Power Rating: 65.2 kW SEDBUK efficiency 79.8%

Ideal: Mexico Super : CF 465
gas : regular : non condensing : floor mounted
Power Rating: 19.1 kW SEDBUK efficiency 79.7%

Ideal: Mexico Super : 480 FF
gas : regular : non condensing : floor mounted
Power Rating: 23.4 kW SEDBUK efficiency 79.7%

Ideal: Classic Slimline : SE18 FF
gas : regular : non condensing : wall mounted
Power Rating: 17.6 kW SEDBUK efficiency 79.7%

Ideal: Classic : SE15 FF
gas : regular : non condensing : wall mounted
Power Rating: 14.7 kW SEDBUK efficiency 79.6%

Optia: FF50 :
gas : regular : non condensing : wall mounted
Power Rating: 14.7 kW SEDBUK efficiency 79.6%

Ideal: Classic : SE15 FF Silver
gas : regular : non condensing : wall mounted
Power Rating: 14.7 kW SEDBUK efficiency 79.6%

Ideal: Mexico Super : 80FF
gas : regular : non condensing : floor mounted
Power Rating: (20.5 – 23.4 kW) SEDBUK efficiency 79.4%

Ideal: Mexico Super : RS 4125
gas : regular : non condensing : floor mounted
Power Rating: 36.6 kW SEDBUK efficiency 79.4%

Ideal: Classic : SE9 FF
gas : regular : non condensing : wall mounted
Power Rating: 8.8 kW SEDBUK efficiency 79.4%

Ideal: Classic : SE9 FF Silver
gas : regular : non condensing : wall mounted
Power Rating: 8.8 kW SEDBUK efficiency 79.4%

Optia: FF30 :
gas : regular : non condensing : wall mounted
Power Rating: 8.8 kW SEDBUK efficiency 79.4%

Ideal: Mexico Super : 460 FF
gas : regular : non condensing : floor mounted
Power Rating: 17.6 kW SEDBUK efficiency 79.2%

Ideal: Classic Slimline : SE12 FF
gas : regular : non condensing : wall mounted
Power Rating: 11.7 kW SEDBUK efficiency 79.2%

Ideal: Classic : FF 360 LF
gas : regular : non condensing : wall mounted
Power Rating: 17.6 kW SEDBUK efficiency 79.1%

Ideal: Classic : FF 340 LF
gas : regular : non condensing : wall mounted
Power Rating: 11.7 kW SEDBUK efficiency 79.1%

Ideal: Mexico Super : RS 450
gas : regular : non condensing : floor mounted
Power Rating: 14.7 kW SEDBUK efficiency 79.1%

Ideal: Mexico Super : RS 485
gas : regular : non condensing : floor mounted
Power Rating: 24.9 kW SEDBUK efficiency 79.1%

Ideal: Mexico Super : 450 FF
gas : regular : non condensing : floor mounted
Power Rating: 14.7 kW SEDBUK efficiency 79.0%

Ideal: Classic : SE18 RS
gas : regular : non condensing : wall mounted
Power Rating: 17.6 kW SEDBUK efficiency 79.0%

Ideal: Mexico Super : RS 470
gas : regular : non condensing : floor mounted
Power Rating: 20.5 kW SEDBUK efficiency 79.0%

Ideal: Mexico Super : CF 4120
gas : regular : non condensing : floor mounted
Power Rating: 35.2 kW SEDBUK efficiency 79.0%

Ideal: Mexico Super : RS 4100
gas : regular : non condensing : floor mounted
Power Rating: 29.3 kW SEDBUK efficiency 79.0%

Ideal: Mexico Super : RS 460
gas : regular : non condensing : floor mounted
Power Rating: 17.6 kW SEDBUK efficiency 79.0%

Ideal: Mexico Super : CF 475
gas : regular : non condensing : floor mounted
Power Rating: (22 – 22.0 kW) SEDBUK efficiency 78.9%

Ideal: Classic : SE12 RS
gas : regular : non condensing : wall mounted
Power Rating: 11.7 kW SEDBUK efficiency 78.9%

Ideal: Mexico Super : 4100 FF
gas : regular : non condensing : floor mounted
Power Rating: 29.3 kW SEDBUK efficiency 78.9%

Ideal: Mexico Super : CF 495
gas : regular : non condensing : floor mounted
Power Rating: 27.8 kW SEDBUK efficiency 78.8%

Ideal: Classic : SE12 FF Silver
gas : regular : non condensing : wall mounted
Power Rating: 11.7 kW SEDBUK efficiency 78.6%

Ideal: Classic : SE12 FF
gas : regular : non condensing : wall mounted
Power Rating: 11.7 kW SEDBUK efficiency 78.6%

Ideal: Mexico Super : RS 440
gas : regular : non condensing : floor mounted
Power Rating: 11.7 kW SEDBUK efficiency 78.6%

Optia: FF40 :
gas : regular : non condensing : wall mounted
Power Rating: 11.7 kW SEDBUK efficiency 78.6%

Ideal: Mexico Super : CF 4140
gas : regular : non condensing : floor mounted
Power Rating: (41 – 41.0 kW) SEDBUK efficiency 78.6%

Ideal: Mexico Super : 4125 FF
gas : regular : non condensing : floor mounted
Power Rating: 36.6 kW SEDBUK efficiency 78.5%

Ideal: Mexico Slimline : CF 440
gas : regular : non condensing : floor mounted
Power Rating: 11.7 kW SEDBUK efficiency 78.5%

Ideal: Mexico Super : CF 445
gas : regular : non condensing : floor mounted
Power Rating: 13.2 kW SEDBUK efficiency 78.5%

Ideal: Mexico Super : CF 455
gas : regular : non condensing : floor mounted
Power Rating: 16.1 kW SEDBUK efficiency 78.5%

Ideal: Classic : SE21 FF
gas : regular : non condensing : wall mounted
Power Rating: 20.5 kW SEDBUK efficiency 78.5%

Ideal: Classic : SE21 FF Silver
gas : regular : non condensing : wall mounted
Power Rating: 20.5 kW SEDBUK efficiency 78.5%

Optia: FF70 :
gas : regular : non condensing : wall mounted
Power Rating: 20.5 kW SEDBUK efficiency 78.5%

Ideal: Mini S28 : 28kW System Boiler
gas : regular : non condensing : wall mounted
Power Rating: (28 – 28 kW) SEDBUK efficiency 78.4%

Ideal: Mexico Slimline : RS 445
gas : regular : non condensing : floor mounted
Power Rating: 13.2 kW SEDBUK efficiency 78.4%

Ideal: Classic : FF 350 LF
gas : regular : non condensing : wall mounted
Power Rating: 14.7 kW SEDBUK efficiency 78.4%

Ideal: Classic : SE9 RS
gas : regular : non condensing : wall mounted
Power Rating: 8.8 kW SEDBUK efficiency 78.3%

Ideal: Classic : SE18 FF Silver
gas : regular : non condensing : wall mounted
Power Rating: 17.6 kW SEDBUK efficiency 78.3%

Ideal: Classic : SE18 FF
gas : regular : non condensing : wall mounted
Power Rating: 17.6 kW SEDBUK efficiency 78.3%

Optia: FF60 :
gas : regular : non condensing : wall mounted
Power Rating: 17.6 kW SEDBUK efficiency 78.3%

Ideal: Mexico Super : 440 FF
gas : regular : non condensing : floor mounted
Power Rating: 11.7 kW SEDBUK efficiency 78.3%

Ideal: Mini S24 : 24kW System Boiler
gas : regular : non condensing : wall mounted
Power Rating: (24.3 – 24.3 kW) SEDBUK efficiency 78.3%

Ideal: Classic : SE24 FF
gas : regular : non condensing : wall mounted
Power Rating: 23.4 kW SEDBUK efficiency 78.1%

Ideal: Classic : SE24 FF Silver
gas : regular : non condensing : wall mounted
Power Rating: 23.4 kW SEDBUK efficiency 78.1%

Optia: FF80 :
gas : regular : non condensing : wall mounted
Power Rating: 23.4 kW SEDBUK efficiency 78.1%

Ideal: Classic : SE30 FF
gas : regular : non condensing : wall mounted
Power Rating: 29.3 kW SEDBUK efficiency 78.0%

Ideal: Classic : SE30 FF Silver
gas : regular : non condensing : wall mounted
Power Rating: 29.3 kW SEDBUK efficiency 78.0%

Optia: FF100 :
gas : regular : non condensing : wall mounted
Power Rating: 29.3 kW SEDBUK efficiency 78.0%

Ideal: Mexico Super : 125FF
gas : regular : non condensing : floor mounted
Power Rating: (29.3 – 36.6 kW) SEDBUK efficiency 77.9%

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.

Worcester: Greenstar R : 28 HE System
gas : regular : condensing : wall mounted
Power Rating: (27.7 – 27.7 kW)
SEDBUK efficiency 90.7%

Worcester: Greenstar R : 29 HE Conventional
gas : regular : condensing : wall mounted
Power Rating: (27.7 – 27.7 kW)
SEDBUK efficiency 90.7%

Worcester: Greenstar 29HE Conventional : ZB 7-29
gas : regular : condensing : wall mounted
Power Rating: (29 – 29 kW)
SEDBUK efficiency 90.7%

Worcester: Greenstar Cdi : 30 Cdi Conventional
gas : regular : condensing : wall mounted
Power Rating: (30.0 – 30.0 kW)
SEDBUK efficiency 90.3%

Worcester: Greenstar Cdi : 30 Cdi System
gas : regular : condensing : wall mounted
Power Rating: (30.0 – 30.0 kW)
SEDBUK efficiency 90.3%

Worcester: Greenstar : 24 Ri
gas : regular : condensing : wall mounted
Power Rating: (24 – 24 kW)
SEDBUK efficiency 90.2%

Worcester: Greenstar Cdi : 40 Cdi Conventional
gas : regular : condensing : wall mounted
Power Rating: (40.8 – 40.8 kW)
SEDBUK efficiency 90.2%

Worcester: Greenstar : 24i System
gas : regular : condensing : wall mounted
Power Rating: (24 – 24 kW)
SEDBUK efficiency 90.2%

Worcester: Greenstar R : 40 HE Conventional
gas : regular : condensing : wall mounted
Power Rating: (40.0 – 40.0 kW)
SEDBUK efficiency 90.1%

Worcester: Greenstar : 12 Ri
gas : regular : condensing : wall mounted
Power Rating: (12.00 – 12.00 kW)
SEDBUK efficiency 90.1%

Worcester: Greenstar : 12i System
gas : regular : condensing : wall mounted
Power Rating: (12 – 12 kW)
SEDBUK efficiency 90.1%

Worcester: Greenstar : 18Ri
gas : regular : condensing : wall mounted
Power Rating: (18.00 – 18.00 kW)
SEDBUK efficiency 90.1%

Worcester: Greenstar : 15Ri
gas : regular : condensing : wall mounted
Power Rating: (15.00 – 15.00 kW)
SEDBUK efficiency 90.1%

Worcester: 14/19 CBi : RSF
gas : regular : non condensing : wall mounted
Power Rating: (14 – 19.05 kW)
SEDBUK efficiency 79.4%

Worcester: 15 Sbi : RSF
gas : regular : non condensing : wall mounted
Power Rating: (6 – 15 kW)
SEDBUK efficiency 79.1%

Worcester: 9/14 CBi : RSF
gas : regular : non condensing : wall mounted
Power Rating: (9 – 14 kW)
SEDBUK efficiency 78.5%

Worcester: 19/24 CBi : RSF
gas : regular : non condensing : wall mounted
Power Rating: (19.05 – 23.45 kW)
SEDBUK efficiency 78.4%

Worcester: 24 Sbi : RSF
gas : regular : non condensing : wall mounted
Power Rating: (15 – 24 kW)
SEDBUK efficiency 78.3%

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.