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Last updated: 19 February 2024

Best Combi Boilers For Home Heating In The UK (2024)

Best Combi Boilers UK

Combi boilers remain the most popular boiler types in the UK today. These compact, space-saving units use condensing technology to operate as efficiently as possible while delivering comfortable levels of heat and hot water throughout your home. What’s more, compared to system boiler prices, the best combi boilers tend to start at lower price points. 

Combi boilers are always worth considering when you’re seeking out a new boiler. Being so popular, there are several top-rated boiler brands offering some of the best-performing boilers on the market. In this article, we’ve picked out 5 of the best options for you to consider to help simplify your search and to give you an idea of what to look out for. 

Once you know which combi boiler you’d like for your home, the next step is to find a reputable installer to carry out the installation. This can be a lengthy process of relentless internet searching and waiting around for installers to get back to you with their quotes. Rather than go through all this alone, use Household Quotes’ trusted comparison service. 

Simply fill out our contact form, and then we’ll connect you directly with up to 3 of the best installers for the job, based on your details. Our service is completely free and you’re under no obligation to accept any of the quotes you receive. 

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Best combi boilers per brand

When getting a new boiler, it’s important to prioritise well-known brands. While they may cost more compared to lesser-known companies, you’ll get high-quality products with advanced features and usually a longer warranty.

Here are 5 of the best combi boilers available in the UK today, according to our extensive market research: 

Each of these brands is well established in the UK heating industry and globally. We’ve selected from the best combi models on offer, providing a range of options in terms of power outputs and price points. Take a closer look at these models below. 

Best Worcester Bosch combi boiler

Best Worcester Bosch combi boiler
Greenstar-8000-Life-Combi-System-Regular

The Worcester Bosch Greenstar 4000 has a sleek modern design, an intuitive full-colour display, and a quiet operation. The ‘Quick Tap’ function helps conserve water, while its compatibility with a 20% hydrogen blend ensures its longevity. 

This range lets you enjoy powerful showers even in low-water pressure areas. This range is backed by a potential 10-year guarantee when installed by a Worcester Accredited Installer. It also features wireless connectivity via Bosch EasyControl. Worcester Bosch combi boiler prices can be expensive. However, this range, compared to some of the other examples in this list, is fairly reasonable. 

Worcester Bosch Greenstar 4000
Fuel typeErP ratingOutput ratingHot water flow rate Dimensions (w x h x d)WarrantyPrice range
Gas (LPG conversion available)94%, A 25kW, 30kW9 – 10.8 litres per minute310 x 724 x 400 mm10 years£1,200 – £1,435
Pros 
  • Which? Best Buy 2023
Cons
  • Lowest flow rate

Best Baxi combi boiler

Best Baxi combi boiler
Baxi Platinum Gas Combi Boiler

The Baxi 600 Combi 2 range is compact and user-friendly with a 7-year parts and labour warranty. Baxi is known for affordable price points across all its products. The cost of Baxi combi boilers, such as the 600 Combi 2 range, is a great example of this budget-friendliness.

The Easy-Fill feature simplifies pressure top-ups without the need for an engineer, ensuring hassle-free maintenance. This boiler is also compatible with the Baxi uSense smart control, allowing convenient operation via a smartphone or tablet. With a pre-heated condensate trap, it minimises the risk of frozen pipes in winter. 

Baxi 600 Combi
Fuel typeErP ratingOutput ratingHot water flow rate Dimensions (w x h x d)WarrantyPrice range 
Gas (with LPG conversion)A24, 30, 36kW10.2, 12.2, 15 litres per minute395 x 700 x 285mm7 years£789 – £1,005
Pros 
  • Most affordable
Cons
  • Shortest warranty

Best Vaillant combi boiler

Best Vaillant combi boiler
Vaillant ecoTEC Plus Combi Store Gas Boiler

The ecoTEC plus combi boiler from Vaillant is a Smart Home Ready and hydrogen-prepared solution for precise heating control and energy efficiency. The myVAILLANT app, along with Apple HomeKit and Amazon Alexa integration, provide convenient remote control. 

The built-in IoniDetect technology enhances efficiency, reduces gas consumption, and minimises wear and tear. With a sleek modern design, the ecoTEC Plus fits neatly into any home. 

It also offers a 10-year guarantee when installed by a Vaillant Advance installer, ensuring peace of mind. This boilers are tested for safe and efficient operation. One downside is that Vaillant combi boiler prices tend to run a little higher compared to the other brands on this list. 

Vaillant ecoTEC plus
Fuel typeErP ratingOutput ratingHot water flow rate Dimensions (w x h x d)WarrantyPrice range 
Gas (with LPG conversion)93-94%, A26, 32, 36, 40kW14.5 – 16.5 litres per minute440 x 720 x 352mm (826 model)10 years£1,100 – £1,500
Pros 
  • Wide range of outputs
  • Most suitable for larger homes
  • Highest flow rates
Cons
  • Most expensive

Best Ideal combi boiler

Best Baxi combi boiler
Ideal Vogue Max Gas Combi Boiler

The Logic Max Combi Boiler by Ideal combines the features of the Logic Plus with the added Ideal System Filter for extended boiler life. It has a compact design for discreet installation, a high-resolution colour screen and comes with a reliable 10-year warranty. 

The sleek modern design is complemented by a quick and easy installation process. With green heating technology compatibility and the option to enhance efficiency with the Halo Combi Wi-Fi thermostat, the Logic Max is designed to excel in the UK climate. Ideal combi boiler prices sit somewhere in the middle compared to the other brands featured in this list. 

Ideal Logic Max Combi 
Fuel typeErP ratingOutput ratingHot water flow rate Dimensions (w x h x d)WarrantyPrice range 
Gas (with LPG conversion)94%, A24, 30, 35kW9.9, 12.4, 14.5 litres per minute395, 700, 278mm 10 years£1,140 – £1,430
Pros 
  • Most suitable for smaller homes
  • Smallest dimensions
  • Highest-rated brand on Trustpilot
Cons
  • Smart controls not included

Best Viessmann combi boiler

Best Viessmann combi boiler
Viessmann Vitodens 111-W (B1LF) Gas Storage Combi Boiler

The Viessmann Vitodens 100-W features a modulating MatriX-Plus cylinder burner and a stainless steel Inox-Radial heat exchanger. It offers a rated input of 8.5 to 199 MBH. This range is smart home ready, equipped with built-in WiFi, a 3.5″ LCD screen, and compatibility with the ViCare app. 

This range comes with an impressive 95% energy efficiency rating, compact design, and zero clearance to combustibles. Offering multiple venting options, and easy installation and service, the Vitodens 100-W ensures clean, efficient, and reliable performance. Viessmann also offers a limited lifetime warranty in residential applications, making it a lasting investment with long-term value.

Viessmann Vitodens 100-W
Fuel typeErP ratingOutput ratingHot water flow rate Dimensions (w x h x d)WarrantyPrice range 
Gas (with LPG conversion)95%, A24, 30, 35kW9.9, 12.4, 14.5 litres per minute500 x 859 x 500mm (smallest in range)12 years£1,230 – £1,353
Pros 
  • Most suitable for smaller homes
  • Most efficient
  • Longest warranty
Cons
  • Largest dimensions
  • Rated most poorly on Trustpilot

If you’re thinking about changing your heating system but don’t know where to start looking for a trusted installer, then you’re not alone. Typically, finding reliable professionals can involve days of thorough research and comparing prices. However, we can simplify the process for you.

Our quotes comparison service can assist you in getting up to 3 free, no-obligation boiler quotes from trusted installers in your area. Simply fill out a quick 30-second form, and you can see prices from various reputable options, allowing you to compare and choose what best suits your needs. Click the button below to get started.

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What is the best combi boiler fuel?

To determine the best combi boiler fuel type we can compare important factors like ongoing central heating costs and environmental impacts. Currently, a gas boiler is still the cheapest heating option with gas being 6.9p/kWh, while electricity is more than 5 times the price at 36.3p/kWh.

Cost of fuel 
Fuel typeGasOilLPGElectricity
Average price (pence/kWh)6.9p9p8.7p36.3

In terms of carbon emissions, gas has the lowest factor at 0.213 kgCO2e/kWh, making it the most environmentally friendly choice. Oil and LPG have higher carbon factors, and electricity falls in between.

Carbon factors
Fuel typeGasOil LPGElectricity
Carbon dioxide equivalent factor (kgCO2e/kWh)0.2130.2980.2400.225

Among the options, gas stands out as the best option since it fuels your heating for less and emits less CO2e per kilowatt-hour than other fuel types. Gas is also a popular choice because of its easy installation and wide accessibility for those on the gas grid. 

Best gas combi boiler

We’ve determined 5 of the best combi boiler options available in the UK currently, as listed above. They’ve been selected according to several important metrics, summarised in the table below. 

Best combi boilers per brand
Most powerful Vaillant ecoTEC plus
Best for smaller homes Ideal Logic Max Combi, Viessmann Vitodens 100-W
Most efficient Viessmann Vitodens 100-W
Most affordable Baxi 600 Combi
Longest warranty Viessmann Vitodens 100-W
Highest rated brand Ideal Logic Max Combi 
Smallest dimensions Ideal Logic Max Combi
Highest flow rates Vaillant ecoTEC plus
Which? Best Buy Worcester Bosch Greenstar 4000

Ultimately, the best combi boiler is the one that aligns with your specific requirements and preferences. For example, smaller homes should consider the Ideal Logic Max Combi or the Viessmann Vitodens 100-W. Meanwhile, larger homes with higher demands for heat and hot water are better suited to the Vaillant ecoTEC plus. 

Best oil combi boiler

Of the oil boilers available in the UK today, we’ve determined that the Envirogreen Popular is one of the best. 

Oil boilers are one of the most popular options for homes off the gas grid. With that being said, these boilers tend to take up a lot of installation space and additional storage space for the oil itself.

Oil-fired combi boiler prices also tend to cost considerably more than other traditional heating options. As shown earlier, oil also has the most significant environmental impact in terms of carbon emissions. 

Envirogreen Popular
Fuel typeErP ratingOutput ratingHot water flow rate (kg/h)Dimensions (w x h x d)WarrantyPrice range
OilA, >90%12-20kW, 20-26kW, 26-35kW1642, 3613945 x 720 x 625mm (smallest model)5 years£2,150 – £2,600
Best oil combi boiler

Envirogreen Popular key features:

  • Exceptional hot water performance
  • Premium weatherproof PVC-coated casings
  • Easily accessible with removable sides
  • Utilises a single high-efficiency Grundfos circulating pump
  • Swift re-heating after hot water usage
  • PCB controller equipped with highly accurate thermistors
  • Fully insulated and acoustically designed for ultra-quiet operation
  • Offers multi-directional flue options
  • Equipped with a high-performance low NOx Elco burner

Best electric combi boiler

Electric Heating Company Mercury Combi Boiler is one of the best electric combi boilers available on the UK market today, according to our research. 

Electric boiler heating is extremely efficient, usually operating at 99-100% efficiency. However, the current cost of electricity in the UK is a major drawback for most people since per kilowatt-hour, electricity is far more than other fuel types. 

Electric Heating Company Mercury Combi Boiler
Fuel typeErP ratingOutput ratingMax. water supply pressure (bar)Dimensions (w x h x d)WarrantyPrice range
ElectricD(Heating) A(Hot Water), 100%12, 14.4, 19, 26kW  10451 x 690 x 258mm (smallest model)5 years£1,400 – £1,700
Best electric combi boiler

Electric Heating Company Mercury Combi Boiler key features:

  • Improved hot water flow rate with Bare Wire Technology
  • Low running noise (32dB)
  • Compatible with underfloor heating systems
  • Swift heat-up times
  • External weather compensation
  • Automatic power modulation
  • Integral system diagnostics
  • Easy-fit connectors and sensors
  • High-temperature cut-out
  • Pressure gauge included
  • ErP smart pump included

Best LPG combi boiler

LPG (liquefied petroleum gas), derived from natural gas and oil extractions, is typically compatible with the best gas combi boilers, including all those listed in this article. This means they are suitable for properties connected to the grid as well as those that are not connected.

How did we choose the best combi boilers?

To find the best combi boilers available in the UK, we considered the following: 

  • Brand: Opt for a reputable boiler brand, even if it means a slightly higher cost. This ensures a reliable appliance that’s less prone to issues.
  • Output Size: Combi boilers come with two output sizes—one for central heating (CH) and one for domestic hot water (DHW). These values indicate the boiler’s power and its ability to meet your house’s heating and hot water demands.
  • Efficiency: The efficiency level of a combi boiler reveals how effectively it converts fuel into usable energy while minimising waste. A higher efficiency translates to lower heating bills.
  • Flow Rate: Assess the hot water flow rate – how much water the combi boiler delivers per unit of time, indicating the system’s efficiency in providing a steady and sufficient hot water supply.
  • Boiler Dimensions: Smaller boilers are space-efficient, making them ideal for homes with limited space. Opting for a compact boiler ensures efficient use of available room while still meeting your heating and hot water needs.
  • Warranty: A lengthy warranty period signifies the brands’ confidence in their product. It also gives you peace of mind that you won’t have to fork out for sudden repairs, should your boiler experience any issues with that period. 
  • Price: New boiler prices are usually based on the quality of the model, the length of the warranty and any special features that it comes with. More powerful boilers designed for larger homes will generally cost more than smaller models. 

Choosing the best combi boiler isn’t a one-size-fits-all scenario. The ideal pick for you depends on how well it aligns with your house’s needs and your budget.

Best combi boiler deal

To minimise the total combi boiler costs, it’s best to shop around for the best installation deals. You can do this by receiving and comparing quotes from multiple local heating engineers, we recommend at least 3.

After acquiring these quotes, compare them, as well as the credibility of the installation companies themselves. This helps make sure that you’re going for the best deal from the most reputable installer. 

However, this method does have a drawback: sifting through numerous suppliers requires several hours of research to find and verify the installers. 

With Household Quotes, we have a whole network of carefully vetted installers based from up and down the UK. Fill out our 30-second form, and we’ll provide you with up to 3 free quotes from the best installers in your area. We’ll only match you with the installers who suit your needs. Besides, there’s no obligation to accept any quote you receive, just tailored, professional quotes provided directly to you. 

Simply click the button below to get started. 

Get your best deal
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Frequently asked questions

Ciaran Wark
Written by Ciaran Wark, Writer

Ciaran is a content writer at Household Quotes. He has become an expert in energy saving and eco-conscious living which he uses to create informative content for Household Quotes readers.

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