Which boiler is the most energy efficient?

06 October 2021

There are so many benefits to investing in a more energy efficient boiler: including reducing your household bills, lowering your carbon footprint, and having a warmer home!


Every home and building has different heating needs, and depending on what your requirements are, there will be an energy efficiency solution tailored to you. 


We’ll be guiding you through everything you need to know about making a greener upgrade when heating your home - from which boiler is best for you, to what size and model.

Which boiler is right for me? 

The first thing you need to consider when choosing an energy efficient boiler, is what boiler you should buy. 


These days, all modern boilers are condensing boilers: which means they are more energy efficient than the older, non-condensing models. 


According to the Energy Savings Trust, you can already save up to £340 a month on bills by trading your old boiler for a newer model!


The three main types of boilers are:


  • A combi boiler: ideal for smaller homes, these boilers heat water as and when you need it - meaning there’s no need for a storage tank.
  • A heat-only boiler: these are better suited for larger properties, that have room for the tank or cylinder where the water will be stored. They’re also known as ‘conventional’ boilers.
  • A system boiler: similar to a heat-only boiler, they work in the same way by needing to store the water they heat. But unlike heat-only boilers, they take their water supply from the mains, delivering high volumes of hot water whilst being more compact.


If you’d like more guidance on which type of boiler is best for your needs, please get in touch with one of our team for a chat.

How is the efficiency of my boiler calculated?

There are two main ways you can calculate your boiler’s energy efficiency. 

The first is to check the percentage on SEDBUK (Seasonal Efficiency of a Domestic Boiler in the UK), and the higher the percentage, the better.


The second is to check your boiler’s ERP (energy-related product) rating: these are graded A-G with A being the best, and G being the worst. Most modern boilers tend to be rated A, but your old boiler could be in the D-G range, so we recommend that you check!

Which size of boiler is right for me?

The next step once you’ve decided which type of boiler you require, is to consider the size of boiler you need. How efficient your boiler is will depend on your individual requirements and how much hot water you expect to use. 


Put into context, the heat output from a boiler is measured in kW (Kilowatts), and the higher the heat output is, the more energy your boiler will use when it’s turned on. 


Normally, larger homes that have more radiators and bathrooms will need a larger heat output than smaller homes - therefore, a different type of boiler will be needed. 

Which models of boiler are most energy efficient?

At Hales & Coultas, we can service, repair and install all types and sizes of boiler.


From our research, here are the most energy efficient models by percentage energy efficiency of system, combi and heat-only boilers:


How else can I improve the efficiency of my boiler?

You can also take boiler efficiency into your own hands, buy making sure that you:


  • Get your boiler service checked annually, by one of our friendly team
  • Keep an eye on your boiler pressure
  • Turn the heating on after long periods of time turned off, to prevent seize-ups
  • Keep your boiler clean and ventilated


By keeping your boiler efficient and your bills down, you’ll also be doing your bit to reduce carbon emissions and help save the planet. So what are you waiting for? Get in touch with us today for a free chat!

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