What Type of Boiler is the Most Energy Efficient?

The process of switching to a different boiler can feel quite confusing to the point of being overwhelming. With so much to think about, from boiler type to boiler brand, it can be difficult to know if the decision you’re making is the right one.

On top of the above, because a boiler is a long-term commitment, hopefully lasting you over 10 years, you also want to be sure the one you buy is energy-efficient. At D A Gas Heating & Plumbing, we specialise in boilers, including their installation and care. We have in depth knowledge of different boiler types and the factors that make them energy-efficient, and have created this guide to help you as you navigate your way through to purchasing a brand new boiler.

Why is energy-efficiency important?

Having a boiler that’s energy-efficient is important for a number of reasons. And in recent years, the government has introduced laws to make energy-efficient boilers essential when being designed and built. The pressure is largely on boiler manufacturers, but it’s important for all of us to be more mindful of the energy we use.

That’s because having a boiler that’s energy-efficient is so much better for the planet, which is suffering an extreme energy crisis. Using a boiler that’s more efficient means that energy gets recycled and fewer damaging CO2 emissions are released into the atmosphere.

The other big advantage of an energy-efficient boiler is saving money. By switching to an A-rated condensing boiler, homeowners can save hundreds of pounds a year on their gas bill, as the less energy you use, the less you have to pay for.   

Compared with many older boilers that work at 70% efficiency, newer boilers can achieve much higher efficiency ratings of 90% and beyond. When you compare the figures, it’s easy to see the difference using an energy-efficient boiler can make. 

Is a combi, system or regular boiler most efficient?

Below we compare these three popular boiler types and consider their efficiency.

Combi boilers

Combi boilers are considered very efficient indeed as there is no water waste with them. They heat hot water as you need it, piping it directly from the mains, so it’s not sat in a tank or cylinder wasting if not used. The only downside is that combi boilers don’t suit bigger homes with more than one bathroom usually as they can only provide hot water to one source at a time.

Regular boilers


Regular boilers work along with a hot water cylinder and a cold water tank, which is usually positioned in the loft. If your regular boiler is A-rated and condensing, it is likely to be energy-efficient and able to recycle some of the energy it uses. The risk with a regular boiler is that because the hot water has to be heated in advance, you may heat more than you need and therefore waste some energy. Regular boilers are usually suitable for houses with more than one bathroom as they can run to multiple sources at once, unlike a combi boiler. 

System boilers

Similar to regular boilers, system boilers require water heating in advance, which then sits in a hot water cylinder until needed. They don’t need a water tank, so they may be more efficient than a regular boiler. System boilers are also suitable for bigger homes with more than one bathroom, and they can integrate with a solar thermal system, so have the potential to be made even more energy-efficient. 

What efficiency boils down to with your boiler...

Whether you opt for regular, system or combi, the main factor to bear in mind with energy-efficiency is whether your new boiler is condensing and A-rated for energy. So long as it is, it’s best to choose a boiler that fits your needs, and will provide you with the amount of hot water and heat you require, without wasting it. Once installed, you can choose to be more mindful with how you use your boiler, with the aim of saving energy and money, as well as helping the planet!

Boiler installation specialists in Essex

The team at D A Gas, Heating & Plumbing provide a safe and expert boiler installation service you can trust. We cover the areas of Bishop's Stortford, Sawbridgeworth, Epping, Stansted, Great Dunmow, Hoddesdon and Ware, and welcome all boiler installation and care enquiries.

If you’d like to find out more about boiler installation, have a question or wish to arrange a quote, simply get in touch. You can contact us by telephone on 07920 875189 or 01279 316304, by email at dave@dagas.co.uk or through our website by filling out our short contact form.