Which Is the Most Energy Efficient Boiler?

what is the most energy efficient boiler

In every part of our lives, we are encouraged to consider how we can reduce our energy consumption. From how we drive and the cars we own through to the appliances in our home. The household boiler providing our supply of hot water and heating is likely to be the appliance which is the biggest user of energy in any household, with the Energy Saving Trust suggesting that this could be up to 50% of the monthly bill. This would also help to justify what a new boiler cost!

That means that boiler efficiency needs to be a top priority. Not only for our bank accounts but also for the environment.

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Q What kind of fuel does your boiler use?

What Is Boiler Efficiency?

Boiler efficiency is all about the difference between the energy used to run your boiler and the energy it produces. Now on most products, you’ll see a big sticker declaring their ERP rating, and this stands for the Energy Related Products directive. The directive aims to allow consumers to quickly see how energy efficient a product will be.

To assess how efficient a new boiler is, an analysis is carried out of the amount of fuel converted to usable energy and then how much fuel is lost during the process. That means that a boiler with an energy efficiency of 94%, loses 6% of the fuel used to produce your heating or hot water.

How Can An Energy Efficient Boiler Save Me Money?

If your boiler was installed before 2005, then there’s a good chance that it’s a non-condensing boiler. That means that it may be less than 60% energy efficient, wasting over 40% of the energy you’re billed for each month. So, if you’re now wondering is a boiler energy efficient, well the newer condensing versions can be.

However, it’s not just the monthly bills where the savings come in. The best combi boilers and best system boilers are designed to last much longer, and so that means that you won’t need to spend money on a  new boiler and installation charges as often as you may have done before.

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Most Energy Efficient Boilers

We’ve researched all the top boiler manufacturers to come up with a list of some of the best energy-efficient gas boilers.

Vitodens 200-W

While the Viessmann Vitodens 200-W combi boiler is designed for larger homes, it achieves an impressive 98% efficiency level. The 200-W comes with a matrix cylinder burner and a combustion controller, resulting in an energy-efficient combi boiler that keeps maintenance costs down.

A boiler must be easy to program to your exact needs, and the 200-W makes it child’s play with an integrated WiFi interface. Should there be a problem, then the installer is instantly informed via the app, meaning that the boiler is always operating at top levels of efficiency.

Ideal Logic Combi C30

The Ideal Logic has earnt its place on our list with its outstanding 94% efficiency level. This compact, wall mounted combi boiler has a 24kW heating output and a hot water output of 30kW, making it an excellent choice for medium-sized homes. Although the two-year warranty is relatively low, it can be extended to five or ten years. Alternatively, taking out a boiler cover plan is a great alternative option. 

The Ideal Logic comes with boiler frost protection, to reduce the chance of your boiler freezing during the winter and a digital display to make it easy to read and set-up.

Worcester Bosch Greenstar 28CDi Compact

Worcester Bosch is one of the best known and respected boiler brands in the UK and this boiler with an ErP rating of 92% makes it onto our list as a powerful option for three-bedroomed homes with one or two bathrooms.

We love all the different options to manage the operation of this boiler. Whether you prefer a mechanical option or the top tech option of an award-winning Hive thermostat, you’ll be able to balance your heating needs with an eye on efficiency. The Greenstar 28CDi comes with a warranty of up to ten years when fitted by a Worcester Accredited Installer.

Vaillant ecoTEC with Green iQ combi

So, the Vaillant ecoTEC just gets on to our list with an efficiency level of between 90 and 92%, but 85% of its parts are recyclable means that this is a boiler with green credentials.  The flow rate of 17.8 litres per minute means fast delivery of hot water literally ‘on tap’. The ecoTEC is compatible with the vSMART™ control meaning that you can control your boiler from a smartphone or tablet.

This is a boiler hand made in Vaillant’s Derbyshire manufacturing plant, and it comes with a five-year warranty which can be extended for another five years when fitted by a Vaillant installer.

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How can I improve the efficiency of my current boiler?

If there’s one key way to maintain efficiency, it’s through ensuring that you get all types of boilers serviced every year without fail. This will enable the engineer to identify any minor problems that might be causing your boiler to work harder than it has to and reduce its efficiency.


When you’re searching for an energy-efficient replacement boiler, the cost will no doubt come into your decision. But don’t forget that efficiency levels will have a direct impact on your monthly fuel costs, and you’ll be doing your bit to reduce carbon emissions.

To see our recommendations for the perfect energy efficient boiler for your home, simply answer a few questions about your heating and hot water needs, and we’ll provide a fixed price cost for your new boiler installation.

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