List of ratings and protocols related to boilers

Like any other electric and energy equipments, boilers too come with a lot of ratings and certifications. As a buyer it is important to understand about these ratings and what they mean for you. Boilers tend to consume a lot of energy if not used appropriately.

ErP rating

ErP Ratings is a recently born European requirement standard set aside for the efficiency of hot water products. ErP Ratings are common to boiler these days and can also be found on other devices like washing machines, televisions, etc. It is a sign which indicates the level of performance and efficiency of the equipment. The efficiency classes ranges from A++ to G where A++ means highest level of efficiency. You can find these ratings in the labels on your boiler. Next time when you plan to buy a new boiler, do check out for the ErP Ratings.

Flow Rate

Flow rate is a term which is associated especially with combination boilers. Flow rate will be mentioned on the boiler manual. Flow rate is the amount of hot water that is coming out of your taps after heating. One important fact to remember with respect to flow rate is that it is totally dependent on the flowrate of your mains. If your combination boiler has a flow rate of 15 litres per minute and your mains flow rate is 10 litres per minute, then your actual output will be 10 instead of 15. At the time of buying, do make sure that the flow rate mentioned is either same or above your mains’ flow rate.

Gas Safe Accreditation

Gas Safe Accreditation is not something that is related to your boiler but is the certificate required by the engineer who can work on your boilers. As per UK law it is mandatory to hire only Gas-Safe certified professional to either install or work on the boilers. Once the purchase of the boiler is made, you have to ensure that the person coming for installation is Gas-Safe certified. You can demand for his ID card and check the Gas-Safe membership in the rear side of the card.

OFTEC Accreditation

This is similar to Gas-Safe except OFTEC is the registrar for engineers who are certified to install and work on oil fired boilers instead of gas. Though it is not mandatory, it is still highly recommended to hire only OFTEC accredited boiler engineers to install and commission your oil-fired boilers.


Greenstar is the terminology related to Gas fired boilers and it signifies high energy efficiency and performance. UK has more than 2 million households fitted with Greenstar rated boilers already.


It is a UK specific rating which specifies seasonal efficiency of the boilers. Efficiency is expressed both with percentage parameter along with A-G ratings. This enables for an easy comparison while choosing the boiler. SEDBUG rating is now combined with ErP and can be seen on the ErP label itself.

We have tried our best to list out most of the commonly found ratings and certifications related to boilers and also boiler engineers so that you can make an educated decision with respect to your boiler purchases.