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What are the Best Combi Boilers in the UK? (2025)
- The best combi boiler for efficiency is the Viessmann Vitodens 100-W with 94 - 98% efficiency.
- The Baxi 800 Combi 2 is the most affordable combi boiler at £1,160 - £1,490 (excluding installation).
- The best combi boiler brand is Worcester Bosch with consecutive ‘Which? Best Buy’ awards, up to 12 years warranty options and excellent customer reviews.
Given the wide range of options available, choosing the right combi boiler for your home can seem daunting. Factors like energy efficiency, reliability, and cost are all crucial, but how do you decide which combi boiler is best?
Well, we’ve found all the answers for you. We’ve reviewed the market and analysed specifications, user reviews, and prices to bring you the most comprehensive and reliable list of combi boilers available today. Our guide will help you navigate the choices and find the perfect fit.
Ready to install a new combi boiler? First, you’ll need to find a qualified heating engineer. Doing this alone can be a mammoth task, scrolling for hours, filling in endless forms, and waiting days to hear back. Avoid wasting your time, and let us help instead.
At GreenMatch, we have a network of qualified, reliable installers who can offer you competitive quotes with no obligations attached. All you have to do is fill in one 30-second form, and we’ll connect you with up to 3 installers in your area.
It’s quick, easy and completely free! Just click below to get started.
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Our best combi boiler review process
At GreenMatch we always want to give you the best, most accurate information on products so that you can make an informed decision. To create our best combi boilers list, we’ve used our own unique process for checking and ranking products based on our analysis of specific areas.
These include researching brands and market options, reviewing technical data, understanding user experiences and calculating cost estimates. This research includes researching the following points:
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Brand reputation
Understanding the manufacturer's history, customer reviews and industry recognition gives a great insight into how their products are received and trusted.
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Fuel types
It’s important to include all fuel types in our research, including gas, oil, LPG and electric options. This ensures that most households are covered in our choices.
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Output sizes
To be part of our ‘best’ list, we must choose options that most homes can use. One element of this is to find boilers with a range of output sizes (this means how powerful they are) and to find products suitable for small and large homes.
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Efficiency levels
The higher the efficiency, the better the boiler - not only because it reduces carbon emissions, but it also saves homeowners significantly on their annual energy bills. So this is a key element we look at, only products above 92% efficiency are considered.
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Warranty
We can tell a lot about a product based on its warranty offer. The longer the cover, the more faith you can have that the boiler is built to last. Warranties of 10 or more years ensure your boiler is protected for most of its lifespan.
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Price
We spend many hours comparing current market prices to ensure we reflect the most accurate cost ranges at the time of publishing. Whilst we can’t guarantee these will be the same forever, it’s a good estimate to help you find a suitable product for your budget.
Using these areas to research and analyse the market, we are confident that our list of best combi boilers is a well-rounded representation of what's on offer. Our list below has been carefully considered to ensure all homes, budgets and needs have a reliable option.
Top 5 most reliable combi boilers in the UK
When it comes to heating your home efficiently and reliably, choosing the right combi boiler is crucial. Based on our extensive research of the UK market, including analysis of specifications, customer reviews, and expert opinions, we've compiled a list of the top 5 most reliable combi boilers available in 2025.
These models stand out for their durability, efficiency, and innovative features, offering homeowners peace of mind and excellent performance. Let's take a closer look at these top-rated combi boilers, their prices, and what makes them stand out from the competition.
1. Viessmann Vitodens 100-W Combi
- Fuel types: Gas, LPG (Liquefied petroleum gas)
- Output sizes: 26kW, 30kW, 35kW
- Efficiency: 94 - 98% (ErP A-rated)
- Warranty/guarantee: 10 - 12 years (terms apply)
- Price range: £1,450 - £1,620 (excluding installation)
The Viessmann Vitodens 100-W Combi boiler comes in at the top of our list for the best combi boilers in the UK, and for good reason.
With a combination of advanced technology, durable components, and smart features, this model is one of the most reliable options on the UK market. It offers homeowners a choice of fuel, a wide range of outputs (to suit multiple home sizes) and an industry-leading efficiency rating.
It’s also a very reasonably priced model for the extensive range of features and the warranty it offers. It ticks nearly all the boxes for a superior yet affordable combi boiler option.
- High efficiency of 94-98% means lower energy costs for homeowners
- Built-in WiFi compatible with Viessmann’s ViCare app, allowing for remote control and monitoring
- High-grade components, like a stainless steel heat exchanger, ensure efficiency, longevity and resistance to corrosion
- Extended warranty of up to 12 years when registered with Viessmann within 30 days
- Slightly more expensive than some competitors
- Requires professional installation
- Some users may need time to learn smart features
- Fewer output options compared to some other brands
2. Worcester Bosch Greenstar 8000+ Combi
- Fuel types: Gas, LPG
- Output sizes: 32kW, 36kW, 40kW, 45kW, 50kW
- Efficiency: 94% (ErP A-rated)
- Warranty/guarantee: 8 - 12 years (terms apply)
- Price range: £1,500 - £2,680 (excluding installation)
The Worcester Bosch Greenstar 8000+ Combi is a high-performance, energy-efficient boiler that has become a popular choice for UK homes.
Worcester Bosch has an outstanding reputation for providing high-quality, long-lasting products that received high praise and recognition from the industry. They consistently win ‘Which? Best Buy’ awards for their models and receive excellent customer feedback.
With its stylish design, wide output ranges, and alternative fuel options, the Greenstar 8000+ is the latest in a long line of highly regarded boiler options, both by customers and installers. This boiler model is a great choice for 3-bedroom homes or even larger, as it can accommodate higher outputs than most other combi options.
- High efficiency of 94% means lower energy bills and reduced carbon emissions
- Vast output options from 32 – 50kW make it suitable for medium to large homes
- Compact design to easily fit into small spaces
- Compatible with smart controls like the Bosch EasyControl, for remote heating management via smartphone apps
- Up to 12-year warranty with accredited installer
- Higher upfront costs compared to basic models
- May exceed hot water requirements for smaller homes
- Smart control integration requires additional purchases
- Too powerful for small homes (1 – 2 bedrooms)
3. Baxi 800 Combi 2
- Fuel types: Gas, LPG
- Output sizes: 24kW, 30kW, 36kW
- Efficiency: 93% (ErP A-rated)
- Warranty/guarantee: Up to 10 years (terms apply)
- Price range: £1,160 - £1,490 (excluding installation)
The Baxi 800 Combi 2 is a popular, high-efficiency, compact combi boiler option. Its lower price range is attractive to homeowners, while the brand has a great reputation among installers.
The 800 Combi 2 has a full range of benefits and features, making it a reliable choice that will last. For example, it boasts a 93% efficiency, and a stainless steel heat exchanger, making it a cost-effective choice for long-term energy savings.
As well as working with gas and LPG, the 800 Combi 2 is also certified to work with 20% hydrogen, aligning with potential future fuel changes. This means you won’t have to change your boiler should the UK switch to a gas-hydrogen blend.
Suitable for small and medium-sized homes with up to 2 bathrooms, its compact size makes it quick and easy to fit, reducing installation time and costs.
- 93% efficiency rating for energy savings
- Quiet operation
- Arrives with an Adey MagnaClean Micro2 system filter to protect the boiler and heating system from debris – furthering its lifespan.
- Compact design fits in standard kitchen cupboards
- Up to 10-year parts and labour warranty available
- Compatible with Baxi uSense smart control for remote management via smartphone or tablet
- Fewer output options compared to some competitors
- May not be suitable for larger homes with high hot water demand (4+ bathrooms)
- Slightly lower efficiencies than other models on the market
4. Vaillant ecoTec Plus
- Fuel types: Gas, LPG
- Output sizes: 26kW, 32kW, 36kW, 40kW
- Efficiency: 93 - 94% (ErP A-rated)
- Warranty/guarantee: 5 - 10 years (terms apply)
- Price range: £1,520 - £2,240 (excluding installation)
The Vaillant ecoTEC Plus is a popular condensing boiler option that is suitable for medium-sized homes with up to 4 bedrooms due to its range of output sizes. This model from Vaillant is known for its stylish appearance and up to 94% efficiency.
The new ecoTEC Plus model is Quiet Mark awarded, recognising its low-level noise design - great for those who need to install a boiler in a busy area. It’s also built with smart technology to allow users to remote control via the vSMART app.
With an extendable warranty of up to 10 years, stainless steel heat exchangers, and IoniDetect technology, Vaillant has built in many ways for this boiler to last the test of time. In addition, it's also compatible with up to 20% hydrogen blend for further future-proofing.
- High efficiency rating for heating and hot water
- Quiet Mark accreditation for low noise operation
- Compatible with Vaillant’s vSMART energy management system
- IoniDetect technology for optimized combustion efficiency
- Designed to accept up to 20% hydrogen blend
- May be more expensive than competitors
- Lower standard warranty than other brands
- Too powerful for small homes (1 – 2 bedrooms)
5. Ideal Heating Logic MAX Combi²
- Fuel types: Gas, LPG
- Output sizes: 24kW, 30kW, 35kW
- Efficiency: 94% (Erp A-rated)
- Warranty/guarantee: Up to 10 years (terms apply)
- Price range: £1,165 - £1,520 (excluding installation)
With an impressive efficiency of 94% and output ranges for standard homes, the Ideal Heating Logic MAX Combi² is an impressive boiler model which offers some of the same great features of the more expensive brands at a fraction of the cost.
This model comes with an Ideal System Filter to maintain, protect, and extend the boiler's lifespan. Ideal also offers up to a 10-year warranty for complete peace of mind.
The Logic MAX Combi² is awarded the Quiet Mark recognition for their 30kW and 35kW models, indicating it’s one of the quietest combi boilers available. Ideal also has an ‘Excellent’ rating on Trustpilot for customer reviews, showing this brand really puts consumers first.
- High efficiency with 94% rating
- Compact design suitable for kitchen cupboards
- Up to 10-year warranty (when registered)
- Quiet operation with Quiet Mark accreditation (30kW, 35kW)
- Compatible with the Halo range and Halo Wifi combi app for remote heating control
- Lower flow rates compared to some competitors
- May not be suitable for larger homes with high hot water demand (5+ bedrooms)
If you’re interested in installing any of our top 5 combi boilers, we recommend finding a qualified heating engineer to help you get started. Connecting with installers on your own can take some time though, spending hours scrolling through reviews and filling in multiple forms.
Let us help you instead! Filling in our 30-second form will give us all we need to find you up to 3 qualified, vetted installers in your area who can give you free no-obligation quotes to compare - so you get the best deal.
Click below to get started.
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Best combi boiler brands in the UK
When it comes to boiler brands you can trust, several are consistently ranked highly as being the best available in the UK. These are the brands we looked at to find our best combi boiler list as each has its own history of innovation, customer satisfaction and industry recognition to back them up.
Worcester Bosch
Since the 1960s Worcester Bosch has grown to become an industry leader in UK heating and hot water products. With multiple awards and recognition, they have earned a glowing reputation.
- ‘Which? Best Buy’ award winner for 14 consecutive years
- Awarded a Royal Warrant for supplying products to the royal family
- Boilers with up to 94% efficiency rating
- Extensive warranty options of up to 12 years
- Excellent customer reviews and aftercare support
Baxi
Truly a household name in the UK, Baxi has become one of the best-recognised boiler brands with a history going back to the 1860s. Their combi boilers offer quick installation at competitive pricing, earning Baxi a favoured position in anyone's list.
- Baxi is committed to sustainability, offering eco-friendly products that reduce emissions
- High efficiency boiler ratings of up to 93%
- Compact designs suitable for kitchen cupboards
- Smart controls with the Baxi uSense app
- Includes features like magnetic filters for system protection
Vaillant
This well recognised German brand is known for being a front running of energy-efficient boiler products. With a long history of heating innovations since the 1870s, Vaillant is often found firmly rooted in any best combi manufacturers list.
- ErP A-rated boilers for both heating and hot water efficiency
- Quiet Mark accreditation for low noise operation
- Compatible with vSMART app for remote heating control
- Rapid hot water delivery of up to 15.9 liters per minute
Ideal Heating
Since 1906, Ideal Heating has consistently been working on new and improved technologies for the home heating market. In recent years, low-carbon solutions have been their focus, and they are one of the only brands to update and improve their models regularly.
- Energy-saving features with high efficiency ratings
- Quiet Mark awarded for reduced noise levels
- Compact designs fitting standard kitchen cupboards
- Committed to quality products and customer service
- Extended warranty options up to 12 years
Viessmann
Another powerhouse in heating technology, Viessmann is highly regarded for its robust stainless steel parts and sustainable solutions. Based in Germany, it has grown to become a global leader in advanced heating engineering.
- Industry leader with up to 98% energy efficient boilers
- Innovative technology including modulating burners
- Compatibility with renewable energy sources
- Inox-Radial stainless steel heat exchangers for durability
Each manufacturer offers combi boiler models that offer high efficiency and reliable technology. Along with high customer satisfaction rates and industry recognition, each brand we’ve mentioned can guarantee a boiler model to perfectly fit your home heating needs.
Should you get a new combi boiler?
Investing in a new combi boiler can be a smart decision for many homeowners. New boiler models are constantly improving in terms of efficiency, longevity and value for money. If your boiler is over 10 years old, or constantly breaking down - it’s worth your time, and money, to replace it.
A new combi boiler can offer the following benefits:
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Savings
With higher efficiencies, modern combi boilers can save you up to £490 a year on heating costs.
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Reliability
With new technology, such as stainless steel components and filters, a new combi boiler is less likely to break down, reducing the risk of unexpected repair costs and inconvenient cold showers.
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Smart features
With most new models offering smart controls, or wifi compatibility, you can manage your heating remotely and optimise energy usage - meaning further savings opportunities.
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Environmental impact
Higher efficiency, and condensing technology, mean lower emissions, helping you reduce your carbon footprint.
If you’re struggling with an old, inconsistent combi boiler, make life easier and get a replacement. While upfront costs can be a barrier, with reduced repairs and higher efficiency, you can make significant long-term savings whilst improving your comfort.
Ready to explore your combi boiler options? We recommend obtaining quotes from several installers in your local area to compare. This way you can find the best deal and price for your budget.
Finding qualified installers on your own can be a stressful task. Scanning endless websites, reading reviews and searching for those hidden costs. Well we can help you avoid all that hassle and hours of fretting.
By filling in our single 30-second form, we can connect you with up to 3 qualified, vetted installers from your area. They can provide you with competitive quotes and quality advice so you can discover which combi boiler is best for your home.
It’s completely free to do, with no-obligation attached! Just click below to get started today.
- Quotes from local engineers
- Payment by finance available
- Save up to £975
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