Most Energy Efficient Boiler

Going for a brand new A-rated combi boiler could be the best thing that’s ever happened to your energy bills. So much so in fact, that according to the Energy Saving Trust, you could trim off an amazing 40%!

The Energy Saving Trust is a useful resource for learning how to reduce your carbon footprint

Here is where you’ll find factual, reliable and trustworthy information to make sure you know what’s important when purchasing a new boiler. As well as this, you’ll also learn about ways you can improve energy efficiency in your home!

How can I improve energy efficiency in my home?

Every home needs to be comfortable heated!

It’s all well and good telling someone that getting a new boiler will improve your home’s efficiency, but there are still things that can be done in the meantime to help out.

Long Term Improvements:

Short Term Improvements:

  • Have thick curtains fitted
  • Have a programmable thermostat installed
  • Replace other appliances with more modern, more efficient models
  • Add insulation to doors and windows
  • Switch energy provider for lower cost option

You may have noticed ‘switch to a new condensing boiler’ as a fairly obvious point to make, which we’ll be going through in a bit more detail later on.

Cavity wall insulation is useful in storing heat and saving you money

‘Cavity Wall Insulation’ is another point often overlooked, but how does it help? Studies carried out over the years suggest that around 35% of heat loss from a typical home escapes via external walls. As well as this, studies suggest that for every square metre of cavity wall insulation you have fitted, you can save over a tonne of carbon dioxide during the course of the average building’s life.

Now let’s move onto the biggest point of curiosity…energy efficient condensing boilers!

Why should I get a new condensing boiler?

Why should I get a new condensing boiler?

To begin with, if your boiler is around 12-15 years old, it’s already going to be a condensing boiler. While there are still condensing boilers that are even older than that, most boilers that are will be non-condensing, which has its own detriments.

Non-condensing boilers are unable to recycle the waste gases that get produced while it’s operating. So any chance to use the heat from these gases that would otherwise escape via the flue, is lost. This is where condensing boilers win the contest.

A condensing boiler – as the name suggests – uses modern condensing technology to ensure that any hot gases that pass through the heat exchanger, gets used to warm up any water returning from your radiators. What does this mean in the long run? That energy wastage is minimalised for you and your home, meaning lower energy bills!

How does an energy efficient condensing boiler save me money?

Technology is always advancing, which means manufacturers are always finding ways for you to save money in the long run with a new boiler. But this won’t mean anything to most unless they’re aware of the effects on their wallet!

In the world of boilers, energy efficiency means less fuel is used to produce similar, if not superior, results. A typical non-condensing boiler purchased years ago would have started off at around 85% efficiency. Due to regular daily use and constant thermal stress, this would eventually be brought down to levels like 75% and even 50%.

How does that work with money?

how can you save money with a new boiler?

Let’s use that same example again of 85% efficiency. This means that for every £100 you put towards your heating, you would already be wasting £15. Spread over the course of a full year and take into account seasonal habits and changes, then you could be looking at more.

A brand new condensing boiler will usually start up at an efficiency level in the early 90s,  but of course it will also depend largely on what boiler you actually end up choosing.

Even if it’s only brands you’ve looked at so far, there are still other ways you can upgrade the efficiency of your boiler. For example, by adding in features such as internet-enabled smart thermostats or weather compensation technology, you could boost the efficiency to reach levels such as 92-94%. Now let’s look at that in money terms: for every £100 you spend on heating using a boiler with these features, you’d only be losing around £6-£8 a year. Not that much at all!

As previously mentioned, the final efficiency level of your boiler will largely depend on which brand and model you actually choose. If we’re talking about high percentages of efficiency, you can’t do much better than the Viessmann Vitodens 200-W boiler which boasts an amazing 98% efficiency.

If you translate all these numbers into savings, you could be taking as much as £500 off your annual energy bills! There’s a lot of ways you can treat yourself with that kind of money!

What’s the most energy efficient combi boiler?

People can sometimes get confused over the difference between a combi boiler and a condensing boiler. The truth is, any combi boiler installed in the last 12-15 years will be a condensing boiler. The ‘Combi’ part refers to the type of boiler it is (other examples of that category include open vent boiler and system boiler).

Let’s see what’s current on the market for most energy efficient combi boiler:

  1. Viessmann Vitodens 200-W Combi

The Viessmann Vitodens 200-W Combi is an excellent example of efficiency

We’ve mentioned its strengths already, but we’ll do it again: the Viessmann Vitodens 200-w Combi is absolutely the most energy efficient combi boiler you can currently buy on the market.

As a manufacturer, German company Viessmann have had many years experience in the commercial sector. They even have boilers in famous landmarks of our capital city, including the Millennium Stadium!

Viessmann eventually made the wise decision to enter the domestic market, and they brought one of the best boilers out there with them.

The Viessmann Vitodens 200-W operates at an efficiency level of 98%. It combines the technology of weather compensation, top-quality component materials and a keen sense of engineering genius to achieve this result, making it a powerful force to be reckoned with in the boiler industry.

Main benefits of the Viessmann Vitodens 200-W:

  • 98% efficiency, one of the best levels in the industry
  • Operates at a volume of 34db, working quietly in the background
  • Inox-radial stainless steel heat exchanger
  • Control through mobile phone or internet connection (with optional Vitoconnect 100W LAN adaptor)
  • Small, compact shape (450mm wide)
  • Energy efficiency rating: A
  • No need for extra LPG Conversion Kit
  • MatriX cylinder burner


  1. ATAG iC Economiser Plus 35 Combi

ATAG originally come from the Netherlands, and have made a strong impression among the heating and boiler industries. The primary heat exchanger made from stainless steel condenses twice, making it a strong contender in the efficiency race with levels at 94% and above.

Main benefits of the ATAG iC Economiser Plus 35:

  • Pre-heat capabilities allow instant hot water
  • Passive Flue Gas Heat Recover Device built-in
  • Built-in outside weather compensation technology
  • ErP Rating: A
  • Compact size
  1. Viessmann Vitodens 100-W Combi

Another entry from Viessmann in the most energy efficient boiler race, the Viessmann Vitodens 100-W is one of the German manufacturer’s best selling condensing boilers in the UK and Europe.

Main benefits of the Viessmann Vitodens 100-W Combi:

  • Compact shape and design
  • Quiet operation with low fan speed
  • Inox Radial Stainless steel heat exchanger
  • Output availability ranges from 4.7 to 35KW
  • Energy Efficiency rating: A
  • Lowered environmental impact and reduced carbon footprint
  • Backlit LCD Touch Screen for easy access
  1. Vaillant ecoTEC exclusive with Green iQ combi

This boiler is another example of one of the most efficient options available. Although their heat exchanger is made from Aluminium rather than stainless steel, it remains one of the manufacturer’s best boilers for low fuel consumption.

On top of this, Vaillant state that 85% of the components and materials from this boiler get recycled once it’s reached the end of its life.

Main benefits of the Vaillant ecoTEC exclusive with Green iQ combi:

  • Available flow rate of 17.8 litres per minute
  • ErP rating: A
  • Compact size and dimensions (720mm x 440mm x 474mm)
  • Quiet boiler, operating silently in the background

Energy Efficient Combi Boilers Installed by BT Morgan Heating Engineers

With over 35 years experience in the industry, our expert engineers provide a professional and reliable service unmatched in quality.

We take pride in the work we do, and do everything we can to ensure our customers are happy with every result. At BT Morgan Heating Engineers, benefits we can provide include:

  • Personalised care and attention before, during and after installation
  • No overheads like with larger companies, quotes for same boilers can come at a lower cost.
  • In the event of a breakdown or service, an engineer or technician from the manufacturer can be at your property within a day or two.

For a FREE, no-obligation quote, click here.