Mistral - Boiler Efficiency Rating

Compare new boilers and assess whether your current boiler needs to be replaced.

A boiler’s energy rating is an indicator of its efficiency when used within an average domestic household. It’s a great benchmark for comparing new boilers and can help you work out how much money you could save on energy bills if you replaced your current boiler with a more efficient model.

You can find out the energy efficiency of your boiler by checking its energy rating; you can do this now by selecting the make and model below.

How efficient is your boiler?

Select your boiler using the dropdown below to find out.

Mistral Boilers

MistralBH 1 50/70Non-CondensingOil85.7%
MistralBH 2 70/90Non-CondensingOil85.7%
MistralBH 50/90 ContractNon-CondensingOil85.7%
MistralBH 90/150 ContractNon-CondensingOil85.7%
MistralBH1-5070Boiler HouseNon-CondensingOil83.4%
MistralBH2-7090Boiler HouseNon-CondensingOil83.4%
MistralBH3 90/120Non-CondensingOil85.7%
MistralBH3-9012Boiler HouseNon-CondensingOil84.9%
MistralBH4 120/150Non-CondensingOil85.7%
MistralBH4-1215Boiler HouseNon-CondensingOil84.9%
MistralC 50/90 PlusNon-CondensingOil82.9%
MistralC 50/90 Standard ContractNon-CondensingOil82.9%
MistralC 90/150 ContractNon-CondensingOil82.9%
MistralC 90/150 Plus ContractNon-CondensingOil82.9%
MistralC1 50/70 PlusNon-CondensingOil82.9%
MistralC1 50/70 StandardNon-CondensingOil82.9%
MistralC2 70/90 PlusNon-CondensingOil82.9%
MistralC2 70/90 StandardNon-CondensingOil82.9%
MistralC3 90/120 PlusNon-CondensingOil82.9%
MistralC3 90/120 StandardNon-CondensingOil85.7%
MistralC3-9012Mega CombiNon-CondensingOil82.1%
MistralC4 120/150 PlusNon-CondensingOil82.9%
MistralC4 120/150 StandardNon-CondensingOil82.9%
MistralC4-1215Mega CombiNon-CondensingOil82.1%
MistralCBH - 5070Boiler HouseCondensingOil92.5%
MistralCBH - 7090Boiler HouseCondensingOil92.5%
MistralCBH 15/26 ContractCondensingOil92.8%
MistralCBH 26/40 ContractCondensingOil93.0%
MistralCBH1 15/20CondensingOil92.8%
MistralCBH2 20/26CondensingOil92.8%
MistralCBH3 - 9012Boiler HouseCondensingOil91.4%
MistralCBH3 26/35CondensingOil93.0%
MistralCBH4 - 1215Boiler HouseCondensingOil91.4%
MistralCBH4 35/40CondensingOil93.0%
MistralCC 15/26 Plus ContractCondensingOil90.0%
MistralCC 15/26 Std ContractCondensingOil90.0%
MistralCC 26/40 plus contractCondensingOil90.2%
MistralCC 26/40 Std ContractCondensingOil90.2%
MistralCC1 - 5070Condensing CombiCondensingOil89.7%
MistralCC1 15/20 PlusCondensingOil90.0%
MistralCC1 15/20 StdCondensingOil90.0%
MistralCC2 - 7090Condensing CombiCondensingOil89.7%
MistralCC2 20/26 PlusCondensingOil90.0%
MistralCC2 20/26 StdCondensingOil90.0%
MistralCC3 - 9012CombiCondensingOil88.6%
MistralCC3 26/35 plusCondensingOil90.2%
MistralCC3 26/35 StdCondensingOil90.2%
MistralCC4 - 1215CombiCondensingOil88.6%
MistralCC4 35/40 plusCondensingOil90.2%
MistralCC4 35/40 StdCondensingOil90.2%
MistralCK 3 - 9012KitchenCondensingOil91.4%
MistralCK1 - 5070KitchenCondensingOil92.5%
MistralCK2 - 7090KitchenCondensingOil92.5%
MistralCK4 - 1215KitchenCondensingOil91.4%
MistralCKUT 15/26 ContractCondensingOil92.8%
MistralCKUT 26/40 ContractCondensingOil93.0%
MistralCKUT 3 - 9012Kitchen UtilityCondensingOil91.4%
MistralCKUT1 - 5070Kitchen UtilityCondensingOil92.5%
MistralCKUT1 15/20CondensingOil92.8%
MistralCKUT2 - 7090Kitchen UtilityCondensingOil92.5%
MistralCKUT2 20/26CondensingOil92.8%
MistralCKUT3 26/35CondensingOil93.0%
MistralCKUT4 - 1215Kitchen UtilityCondensingOil91.4%
MistralCKUT4 35/40CondensingOil93.0%
MistralCOD - 5070Outdoor ModelCondensingOil92.5%
MistralCOD - 7090Outdoor ModelCondensingOil92.5%
MistralCOD - C - 5070Outdoor CombiCondensingOil89.7%
MistralCOD - C - 7090Outdoor CombiCondensingOil89.7%
MistralCOD - SS - 5070Outdoor Sealed SystemCondensingOil92.5%
MistralCOD - SS - 7090Outdoor Sealed SystemCondensingOil92.5%
MistralCOD 15/26 ContractCondensingOil92.8%
MistralCOD 26/40 ContractCondensingOil93.0%
MistralCOD SS 15/26 ContractCondensingOil92.8%
MistralCOD1 15/20CondensingOil92.8%
MistralCOD1 SS 15/20CondensingOil92.8%
MistralCOD2 20/26CondensingOil92.8%
MistralCOD2 SS 20/26CondensingOil92.8%
MistralCOD3 - 9012OutdoorCondensingOil91.4%
MistralCOD3 - C - 9012Outdoor CombiCondensingOil88.6%
MistralCOD3 - SS - 9012Outdoor Sealed SystemCondensingOil91.4%
MistralCOD3 26/35CondensingOil93.0%
MistralCOD4 - 1215OutdoorCondensingOil91.4%
MistralCOD4 - C - 1215Outdoor CombiCondensingOil88.6%
MistralCOD4 - SS - 1215Outdoor Sealed SystemCondensingOil91.4%
MistralCOD4 35/40CondensingOil93.0%
MistralCODC 15/26 Plus ContractCondensingOil90.0%
MistralCODC 15/26 Std ContractCondensingOil90.0%
MistralCODC 26/40 plus contractCondensingOil90.2%
MistralCODC 26/40 Std ContractCondensingOil90.2%
MistralCODC1 15/20 PlusCondensingOil90.0%
MistralCODC2 20/26 PlusCondensingOil90.0%
MistralCODC2 20/26 StdCondensingOil90.0%
MistralCODC3 26/35 plusCondensingOil90.2%
MistralCODC3 26/35 StdCondensingOil90.2%
MistralCODC4 35/40 plusCondensingOil90.2%
MistralCODC4 35/40 StdCondensingOil90.2%
MistralCODSS 26/40 ContractCondensingOil93.0%
MistralCODSS 3 26/35CondensingOil93.0%
MistralCODSS 4 35/40CondensingOil93.0%
MistralCS 15/26 ContractCondensingOil92.8%
MistralCS 26/40 ContractCondensingOil93.0%
MistralCS1 - 5070Sealed SystemCondensingOil92.5%
MistralCS1 15/20CondensingOil92.8%
MistralCS2 - 7090Sealed SystemCondensingOil92.5%
MistralCS2 20/26CondensingOil92.8%
MistralCS3 - 9012Sealed SystemCondensingOil91.4%
MistralCS3 26/35CondensingOil93.0%
MistralCS4 - 1215Sealed SystemCondensingOil91.4%
MistralCS4 35/40CondensingOil93.0%
MistralKUT 1 50/70Non-CondensingOil85.7%
MistralKUT 2 70/90Non-CondensingOil85.7%
MistralKUT 50/90 ContractNon-CondensingOil85.7%
MistralKUT 90/150 ContractNon-CondensingOil85.7%
MistralKUT1 5070Kitchen UtilityNon-CondensingOil83.4%
MistralKUT2-7090Kitchen UtilityNon-CondensingOil83.4%
MistralKUT3 90/120Non-CondensingOil85.7%
MistralKUT3-9012Kitchen UtilityNon-CondensingOil84.9%
MistralKUT4 120/150Non-CondensingOil85.7%
MistralKUT4-1215Kitchen UtilityNon-CondensingOil84.9%
MistralLo-Nox BF CBH 1 15/20CondensingOil94.1%
MistralLo-Nox BF CBH 2 20/27CondensingOil94.1%
MistralLo-Nox BF CBH 3 27/35CondensingOil94.1%
MistralLo-Nox BF CBH 4 35/42CondensingOil94.1%
MistralLo-Nox BF CC1 15/20CondensingOil91.3%
MistralLo-Nox BF CC1 Plus 15/20CondensingOil91.3%
MistralLo-Nox BF CC2 20/27CondensingOil91.3%
MistralLo-Nox BF CC2 Plus 20/27CondensingOil91.3%
MistralLo-Nox BF CC3 27/35CondensingOil91.3%
MistralLo-Nox BF CC3 Plus 27/35CondensingOil91.3%
MistralLo-Nox BF CC4 35/42CondensingOil91.3%
MistralLo-Nox BF CC4 Plus 35/42CondensingOil91.3%
MistralLo-Nox BF CKUT 1 15/20CondensingOil94.1%
MistralLo-Nox BF CKUT 2 20/27CondensingOil94.1%
MistralLo-Nox BF CKUT 3 27/35CondensingOil94.1%
MistralLo-Nox BF CKUT 4 35/42CondensingOil94.1%
MistralLo-Nox BF COD1 15/20CondensingOil94.1%
MistralLo-Nox BF COD2 20/27CondensingOil94.1%
MistralLo-Nox BF COD3 27/35CondensingOil94.1%
MistralLo-Nox BF COD4 35/42CondensingOil94.1%
MistralLo-Nox BF CODC1 15/20CondensingOil91.3%
MistralLo-Nox BF CODC1 Plus 15/20CondensingOil91.3%
MistralLo-Nox BF CODC2 20/27CondensingOil91.3%
MistralLo-Nox BF CODC2 Plus 20/27CondensingOil91.3%
MistralLo-Nox BF CODC3 27/35CondensingOil91.3%
MistralLo-Nox BF CODC3 Plus 27/35CondensingOil91.3%
MistralLo-Nox BF CODC4 35/42CondensingOil91.3%
MistralLo-Nox BF CODC4 Plus 35/42CondensingOil91.3%
MistralLo-Nox BF CODSS1 15/20CondensingOil94.1%
MistralLo-Nox BF CODSS2 20/27CondensingOil94.1%
MistralLo-Nox BF CODSS3 27/35CondensingOil94.1%
MistralLo-Nox BF CODSS4 35/42CondensingOil94.1%
MistralLo-Nox BF CS1 15/20CondensingOil94.1%
MistralLo-Nox BF CS2 20/27CondensingOil94.1%
MistralLo-Nox BF CS3 27/35CondensingOil94.1%
MistralLo-Nox BF CS4 35/42CondensingOil94.1%
MistralOD 1 50/70Non-CondensingOil85.7%
MistralOD 2 70/90Non-CondensingOil85.7%
MistralOD 50/90Non-CondensingOil85.7%
MistralOD 90/150 ContractNon-CondensingOil85.7%
MistralOD C1 50/70 PlusNon-CondensingOil82.9%
MistralOD SS 50/90 ContractNon-CondensingOil85.7%
MistralOD SS 90/150 ContractNon-CondensingOil85.7%
MistralOD-C1-5070Outdoor CombiNon-CondensingOil80.6%
MistralOD-C2-7090Outdoor CombiNon-CondensingOil80.6%
MistralOD1 SS 50/70Non-CondensingOil85.7%
MistralOD1-SS-5070Outdoor Sealed SystemNon-CondensingOil83.4%
MistralOD2 SS 70/90Non-CondensingOil85.7%
MistralOD2-SS-7090Outdoor Sealed SystemNon-CondensingOil83.4%
MistralOD3 90/120Non-CondensingOil85.7%
MistralOD3 SS 90/120Non-CondensingOil85.7%
MistralOD3-9012Outdoor ModelNon-CondensingOil84.9%
MistralOD3-C-9012Outdoor Mega CombiNon-CondensingOil82.1%
MistralOD3-SS-9012Outdoor Sealed SystemNon-CondensingOil84.9%
MistralOD4 - 1215Outdoor ModelNon-CondensingOil84.9%
MistralOD4 120/150Non-CondensingOil85.7%
MistralOD4 SS 120/150Non-CondensingOil85.7%
MistralOD4-C-1215Outdoor Mega CombiNon-CondensingOil82.1%
MistralOD4-SS-1215Outdoor Sealed SystemNon-CondensingOil84.9%
MistralODC 3 90/120 PlusNon-CondensingOil82.9%
MistralODC 50/90 Plus ContractNon-CondensingOil82.9%
MistralODC 50/90 Standard ContractNon-CondensingOil82.9%
MistralODC 90/150 PlusNon-CondensingOil82.9%
MistralODC 90/150 StandardNon-CondensingOil82.9%
MistralODC1 50/70 StandardNon-CondensingOil82.9%
MistralODC2 70/90 PlusNon-CondensingOil82.9%
MistralODC2 70/90 StandardNon-CondensingOil82.9%
MistralODC3 90/120 StandardNon-CondensingOil82.9%
MistralODC4 120/150 PlusNon-CondensingOil82.9%
MistralODC4 120/150 StandardNon-CondensingOil82.9%
MistralS1 50/70Non-CondensingOil85.7%
MistralS1-5070Sealed SystemNon-CondensingOil83.4%
MistralS2 70/90Non-CondensingOil85.7%
MistralS2-7090Sealed SystemNon-CondensingOil83.4%
MistralS3 90/120Non-CondensingOil85.7%
MistralS3-9012Sealed SystemNon-CondensingOil84.9%
MistralS4 120/150Non-CondensingOil85.7%
MistralS4-1215Sealed SystemNon-CondensingOil84.9%
MistralSS 50/90 ContractNon-CondensingOil85.7%
MistralSS 90/150 ContractNon-CondensingOil85.7%

What are SEDBUK Efficiency Ratings?

From 1999 to 2015 boilers were ranked on the SEDBUK scale which stands for ‘Seasonal Efficiency of a Domestic Boiler in the UK’. While many still refer to SEDBUK as the standard energy rating scale, it was actually replaced in 2015 by the Energy related Products directive, or ErP. It’s directly related to the EU’s ambition to improve the energy efficiency of our homes and achieve the following targets by 2020:

  • 20% reduction in EU greenhouse gas emissions (compared to 1990 levels)
  • 20% improvement in overall energy efficiency (across the EU)
  • 20% more energy produced from renewable resources such as solar or biomass.

Under the current ErP standards, boiler manufacturers are required to label their products with a rating from A++ to G, with G being the least efficient a boiler can be. In September 2019, efficiency grade A+++ will be added and the least efficient class, G, will be removed as an option, removing these products from the market as a result.

How Much Money Could I Save with a More Efficient Boiler

To understand how a new boiler could save you money, you need to consider the energy that an inefficient boiler is wasting. For example, if a boiler is only 70% efficient, for every £1 you spend on heating your home, 30p is being wasted on lost energy. If your new boiler can reach efficiency of 90%, that is just 10p lost of every £1. So that’s a saving of 20p in every £1 which really adds up over time.

The financial savings you could make by replacing your boiler with a more efficient model can be significant, but will vary depending on the size of your home, the fuel used by the boiler and the inefficiency of your existing boiler.

According to the Energy Saving Trust: “Replacing an old gas boiler with a programmer and room thermostat, with a new A-rated condensing boiler with a programmer, room thermostat and thermostatic radiator controls (TRVs) could save you:

Old Boiler ErP RatingEfficiencyDetached houseSemi-detached houseMid-terrace house
D78 – 82%£170£110£100
E74 – 78%£190£125£105

Figures taken from the latest research by the Energy Saving Trust. Based on fuel prices as of April 2017.

For new boiler installations visit Boiler Guide to request quotes from independent local and regional heating engineers.