Best Condensing Boilers for 2022

Best condensing boilers
worcester 2000 condensing combi boiler

5 best condensing boilers on the market right now

Choosing the best condensing boiler to buy is a big decision, and it can really feel as if the pressure is on to know precisely which is the right one for you and your home.

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You could save up to £580 per year on energy bills with a new A-rated condensing boiler as per the Energy Saving Trust.

In this article, we’re aiming to bring you some clarity on what condensing boilers are, what a brand new boiler cost, and if they’re the right option for you. Sometimes called condenser boilers too, these boilers are super-efficient and help keep home heating costs down.

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What is a gas condensing boiler?

A gas condensing boiler is a boiler that utilises the heat of its gas to warm the water within your home’s heating system. Any waste gasses are recirculated back through the boiler to be reused and burnt so that there is far less waste and by-products.

condensing combi boiler

With non-condensing boilers, that heat is lost as hot gases disappear into the flue. This is why the government has strict guidelines on new boilers that are manufactured in the UK.

Are all gas boilers condensing?

Yes, all new gas boilers have to be gas condensing boilers. While condensing boilers are a type of boiler, it’s important to understand that the term gas condensing is not a specific type but covers new modern gas boilers that have a gas condenser and is a technology built into it.

Are hydrogen-ready boilers condensing?

Definitely. these are the latest energy-efficient boilers to be introduced in the market to help combat climate change. Being hydrogen-ready gas boilers means that they can run on up to 20% hydrogen blend with natural gas.

Therefore the flue gas heat recovery system still has to be in place until the switch over to completely hydrogen where it will still be used but it won’t matter as much! as the only by-product from hydrogen is water. There are no carbon emissions.

Types of condensing gas boilers in the UK

As we have said, the term condensing covers all new gas boilers, they can still be either a combi boiler, a system boiler, or a conventional boiler.

Gas condensing combi boilers

Gas condensing combi boilers are the most installed type of boiler in the UK. Combination boilers provide both hot water and heating from a single unit. This makes them the most desirable for homes where space is at a premium. All new combi boilers that are manufactured in the uk have to include gas condensing technology.

gas condensing system boilers

Gas condensing system boilers

Gas condensing system boilers are also another popular choice in the Uk but for larger homes. System boilers with condensing technology still require a hot water tank to work. This means that they heat up water which is stored in a hot water cylinder that is insulated ready for use when you need it. System boilers in the UK are conensing.

Gas condensing conventional boilers

Gas condensing conventional boilers are great for large homes with low water pressure. The difference between this condensing boiler and a system boiler is that they require a cold water tank as well as a hot water tank to work. These types of boilers are becoming less and less common in the UK but they do still have their place. All heat only or regular boilers as they are known are condensing gas boilers.

The impact of the difference between condensing and non-condensing boilers is immense. Condensing systems lose less than 10% of the heat generated, something completely unobtainable for the non-condensing boiler.

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How do condensing boilers work?

energy efficient condensing combi boiler

Just as with older types of systems, the condensing boiler burns gas to be able to heat the water. This then produces both carbon dioxide and water vapour. You will be able to tell if you have this type by checking if you have a boiler condensate pipe coming out of your home.

The larger heat exchanger in the condensing boiler allows it to recycle the heat within the gases which would otherwise be completely lost through the flue to outside of the home. This is how it saves you money on your energy bills.

Are condensing combi boilers the best?

Condensing combi boilers are one of the most popular types of gas boilers in the UK. This is because they do not require the extra space that a condensing system boiler or condensing conventional boiler does.

Gas condensing combi boilers are compact, energy-efficient, and provide instant hot water only when required. A condensing combi boiler is perfect for most small to medium-sized homes in the UK. As most of the UK has a condensing boiler, if any issues arise then there is always someone on hand to fix it. But, one of the most common problems is a frozen condensate pipe, which as you can imagine you can just defrost yourself!

Best condenser boilers by model

Now each manufacturer has a whole range of boilers to choose from, though the combi boiler is the most popular gas boiler installed in the UK.

The combi is the only boiler that heats water on demand, meaning there is no need for water tanks or hot water storage cylinders. So, we’ve selected just one condensing combi boiler from each one to showcase the features that are on offer.

worcester bosch 4000 condensing boiler

1. Worcester Bosch Greenstar 4000 gas condensing boiler

The Worcester Bosch Greenstar 4000 boiler is the most popular boiler in the Worcester Bosch range and these hydrogen ready boilers are designed for smaller homes with a single bathroom. Since its release, it has fast become one of the best-selling gas condensing boilers in the UK

This is a boiler that is very easy to set-up to provide you with your perfect hot water and heating needs. As a low energy boiler, electrical usage is reduced, and when installed with the internet connected Bosch EasyControl the Greenstar 4000 achieves an A+ ErP efficiency rating. Arguably the best combi boiler on the market.

viessmann vitodens 100-w combi boiler

2. Viessmann Vitodens 100-W gas condensing boiler

Designed for the smaller well-insulated home, the Viessmann 100-W boiler, an efficient and affordable boiler.  Available with the Viessmann tado° thermostat and smartphone app, meaning that you can control your heating system no matter where you are in the world. Available in a range of outputs from 4.7 to 35kW.

The Viessmann Vitodens 100-w combi boiler is one of the best-selling gas condenser boilers in Europe. It is compact and comes in a range of outputs perfect for homes in the UK

3. Baxi 800 gas condensing boiler

baxi condensing boilers

Built-in the UK, this combination boiler comes with an impressive 10-year parts and labour warranty.

It’s small enough to fit into a kitchen cabinet and comes with the Adey Micro2 magnetic system filter to protect and extend the heating system and boiler’s life.

This Baxi condensing boiler comes with a choice of three power outputs, 25, 30 and 36kW.

4. Vaillant ecoTEC plus Combination Store gas condensing boiler

This innovative boiler is a great choice for larger households. That’s because it combines the convenience of the combi boiler with the hot water storage associated with system or regular heating systems.

The water storage is integrated into the back of the boiler, meaning there is no need for a separate hot water tank. The ecoTEC plus delivers 20 litres of hot water per minute and all within 5 seconds.

5. Alpha Combi E-TEC Plus gas condensing boiler

alpha etec condensing boilers

Alpha has gone with stainless-steel heat exchangers for the E-TEC Plus which are designed to be easy to maintain and energy-efficient.

Then Alpha has gone with the high-efficiency Grundfos pump and hydroblock assembly, and zinc plated expansion vessel which reduces the effects of corrosion.

The E-TEC comes in 28, 32 and 38kW models with an LPG model available for those homes not connected to a natural gas supply.

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Cost of condensing boilers

To help you choose, we’ve researched the latest gas boiler prices for all five of the best combi condensing boilers that we’ve mentioned in this article. You can be sure that if you choose one of these energy efficient A-rated boilers that you may even save money on your gas bill.

If you have an old G-rated boiler that is non-condensing, you can save up to £580 per year on your gas bill as per the Energy Saving Trust.

Condensing boiler price guide

ManufacturerModelCondensing Boiler Price
AlphaCombi E-TEC Plus£800
Baxi800 Combi£930
VaillantecoTEC plus Combination Store£1,700
ViessmannVitodens 100-W£1,169
Worcester BoschGreenstar i£1,048
Boiler Prices by Brand

Benefits of new condensing boilers

Here, we explore three key benefits of a condensing boiler:

1. Energy efficient for a greener home

hot water efficiency

Non-condensing boilers can operate at less than 60% efficiency. So that means that 40% of your fuel costs are disappearing up the flue. If your boiler is over ten years old, then that probably means that it’s a low efficiency non-condensing type and you should consider a boiler replacement.

2. Cost efficient & help you save money

A high efficiency condensing boiler will save you money due to the energy and heat which is being saved and recycled. The Energy Saving Trust estimates that the average UK household spends more than half of its energy expenditure on providing heating and hot water. With these types of savings, you’ll see a big difference in the monthly bills.

3. Reduction of carbon footprint

As a condensing boiler generates lower carbon emissions levels than you can do your bit for the environment.

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Best condensing boilers – By brand

We’ve identified five key boiler manufacturers who can supply you with the perfect heating system for your home.

Worcester Bosch

Originally trading as Worcester, they became part of the Bosch Group thirty-four years later in 1996. Worcester Bosch has two manufacturing plants in the UK, in Worcester itself and then one in Derbyshire.

Worcester Bosch has been voted as one of the top recommended brands by YouGov, featuring in the top ten best brands for domestic appliances.


Baxi have been UK manufacturers of heating systems since 1866. Employing more than 6,000 people worldwide in over 100 countries, Baxi is Endorsed by Which? Trusted Traders for their customer service, installation and servicing. A fantastic British new boiler company


Vaillant UK is a family-owned company that has operated for over 140 years. Vaillant Group has a presence in over 20 countries and is the second-largest European manufacturer in the heating sector. When you’re looking searching for ideal condensing boilers, reviews can be important, and Vaillant scores an impressive 4.6/5 on Trustpilot.

viessmann condensing boiler


Johann Viessmann founded the company in 1917 in Germany. Now, it’s a global business with over 12,300 employees worldwide. Viessmann claim to provide the UK’s most reliable boilers and consistently appear in Which? Best Buy lists. In 2019, Viessmann were named as the top Energy & Heat brand for 2019, in their home country of Germany.

alpha logo condensing boilers


Although Alpha has only been in the heating industry for around 50 years, they are part of Immergas, which operates in 30 countries worldwide. Alpha have achieved a very impressive 4.8/5 on Trustpilot for their replacement boilers, a tremendous achievement for this smaller organisation.

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Don’t forget that boiler installation costs need to be added to these prices and that many manufacturers require you to use a Gas Safe registered installer to validate the warranty.

Condensing boiler review summary

Condensing boilers are not only highly efficient, but they are also cheap boilers to run and better for the environment. We know that getting to grips with the different types of boilers can be challenging, whether that’s going for gas or oil, or understanding the right boiler size for your home.

This is why the Boiler Central fixed price quote finds the best boiler deals for your home. Simply answer a few questions about your heating and hot water needs and you’ll see the most suitable boilers suggested for you, it’s that easy!

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