What are the best 30kW combi boilers available in 2023?
If you’re in the market for a reliable and efficient combi, you’ve come to the right place. In this blog, we’ll explore the world of combi boilers and dive into the best options available to your home. We’ll take an in-depth look at the top 30kW combi boilers available on the market today, and explore their features, benefits, and notable considerations to ensure you find the perfect match for your home.
Whether you’re replacing an old combi boiler or installing a new system, our aim is to provide you with all the valuable insights and recommendations you need to help you make the right decision.
Our expert team has extensively researched and analysed various 30kW combi boilers to bring you our comprehensive list of the top 5 boilers. We understand the importance of a reliable heating system, so we’ve taken into account factors such as; energy efficiency ratings, performance, user reviews, and industry recommendations.
So, if you’re ready to find the best 30kW combi boilers for your home, let’s dive in! But first let’s talk about combis…
What do we mean by a ‘combi’ boiler?
Combi boilers are the most common boiler type in the UK, providing a combination (hence ‘combi’) of hot water and central heating from within one unit. Combi boilers’ popularity lies in their comparatively compact size, high efficiency and overall affordability when compared with other boiler types.
How does a combi boiler work?
In simple terms, with a combi boiler, water is supplied directly from the mains, a gas burner is ignited when the tap is turned on, and the heat exchanger transfers the energy to the water, which heats it up, ready for you to use.
Combi boilers are the best boilers for smaller homes with limited space and for those who need hot water and central heating on demand. Modern boilers are designed with a built-in pre-heat system, which helps to deliver hot water even more quickly; this is a small reservoir of water that is kept at a specific temperature, meaning you will have instant hot water as soon as you turn the tap on.
Should I get a 30kW boiler?
If you’re wondering what size boiler you need to heat your home, check out our blog.
Choosing the right boiler size for your needs depends on various factors, such as the size of your property, insulation levels, hot water demand, and heating requirements.
A 30kW combi boiler is suitable for larger properties with multiple bathrooms and high demand for hot water and heating. However, it may be oversized for smaller homes or apartments with lower heating requirements. Oversized boilers can lead to inefficient operation, higher energy consumption, and increased costs.
For a typical three or four-bedroom house with approximately ten radiators, a small to medium-sized boiler (such as one with a capacity of 24-30 kW) should be adequate. However, if you have a larger house with a greater number of radiators or an en-suite bathroom, a larger boiler, typically ranging from 30-35 kW, would generally be more suitable.
The top five 30kW boilers in the UK

1. Worcester Bosch Greenstar 8000 Style 30kW (premium model)
When it comes to reliable and efficient heating solutions, Worcester Bosch is a name that stands out. Among their impressive lineup, the Worcester Bosch Greenstar 8000 Style 30kW combi boiler offers a winning combination of performance, reliability, and contemporary design.
The Worcester Bosch Greenstar 8000 Style 30kW boiler is a top-of-the-line boiler that combines cutting-edge technology, exceptional performance, and sleek design. With its impressive 30kW output, it is suitable for medium to large properties with higher heating demands, ensuring efficient and reliable warmth throughout.
Worcester Bosch Greenstar 8000 Style 30kW is a wall-hung unit and Worcester Bosch’s most powerful combi range. This boiler can run on a 20% hydrogen blend it can help prolong the lifestyle and energy efficiency of the boiler.
This Worcester Bosch Greenstar 8000 Style 30kW excels in energy efficiency, boasting an A-rated efficiency and ErP compliance, which helps reduce energy consumption and lower heating costs. The intelligent controls offer effortless management of your heating system, whether through traditional controls or wireless connectivity using the Bosch EasyControl app. Moreover, its stylish appearance, with a choice of black or white fascia options and a modern touchscreen display, adds a touch of elegance to any home. The Worcester Bosch Greenstar 8000 Style 30kW combi boiler is a perfect combination of performance, efficiency, and aesthetic appeal, providing you with comfort, convenience, and peace of mind.
Worcester Bosch Greenstar 8000 Style technical spec
- Efficiency: A-rated (94%)
- Suitable for: Medium sized homes
- Hot water flow rate: 12.3 l/pm
- Dimensions: Height 780mm, Width 440mm, Depth 360mm
- Warranty: 10-year guarantee
- Colour: White (Life) or black (Style)
- Cost including installation: starting from £2915.
Additional features:
- Easy installation, servicing and maintenance.
- Robust and simple to fit.
- Reduced lift weight compared to the CDi Classic.
- A new clean, modern design.
- Full wireless connectivity with the Bosch EasyControl.
- Same pipe connections, flue and fixing points for ‘simple switch’ with CDi Classic.

2. Worcester Bosch Greenstar 4000 30kW (premium model)
The Worcester Bosch Greenstar 4000 combi boiler is a top-of-the-line gas boiler that is designed for efficiency, reliability, and ease of use.
The Worcester Bosch Greenstar 4000 is an extremely efficient gas-fired condensing boiler designed to provide your home with reliable and affordable heating and hot water.
The Worcester Bosch Greenstar 4000 is engineered to deliver exceptional performance, high energy efficiency, and low emissions – making it the perfect choice for those who want to reduce their carbon footprint and save on energy bills. Saving the planet and the pennies!
The Greenstar 4000 features a sleek and modern design that blends seamlessly into any home decor, and it’s available in a range of sizes to suit different heating and hot water needs.
This fantastic boiler is also packed with advanced features, including a powerful modulating pump that ensures optimum efficiency and performance, a high-efficiency heat exchanger that maximises heat transfer, and a user-friendly control panel that allows you to adjust settings and monitor performance.
Worcester Bosch Greenstar 4000 technical spec
- Energy Efficiency: A-rated (94%)
- Suitable for: Medium sized homes.
- Hot water flow rate: 12.3 l/pm
- Dimensions: Height 710mm, Width 400mm, Depth 310mm
- Warranty: 10-year guarantee
- Cost including installation: starting from £2219

3. Viessmann Vitodens 100-w 30kW (premium model)
The Viessmann Vitodens 100-W 30kW boiler is a highly regarded heating system that combines advanced technology, energy efficiency, and reliable performance. Designed for medium to large homes, this boiler provides ample heating power with its 30kW output, ensuring optimal comfort even in properties with higher heating demands. The Vitodens 100-W boasts a high energy efficiency rating, allowing you to reduce energy consumption and lower your heating costs. Its stainless steel heat exchanger maximises heat transfer efficiency, providing consistent warmth throughout the home while minimising energy wastage.
The boiler features advanced modulation technology that adjusts the heat output according to the heating demand, resulting in precise and efficient operation. With its user-friendly interface and intuitive controls, homeowners can easily manage and customise their heating settings. The Vitodens 100-W also offers compatibility with smart home systems, allowing for remote control and monitoring.
With its cutting-edge smart technology and services, the Vitodens 100-W enables you to optimise your heating system and reduce your energy costs.
Moreover, it’s a hydrogen-ready boiler, which can run on a 20% hydrogen blend, adding to its versatility.
The integration of WiFi control functionality enhances its efficiency, allowing for remote monitoring and adjustment without the need for additional controls.
Known for their reliability and durability, Viessmann boilers are built to last and backed by excellent customer support. In conclusion, the Viessmann Vitodens 100-W 30kW boiler offers exceptional energy efficiency, reliable performance, and convenient controls, making it a popular choice for homeowners seeking a high-quality heating solution.
Viessmann Vitodens 100-w 30kW technical spec
- Energy Efficiency: A-rated (98%)
- Hot water flow rate: 12.4 l/pm
- Dimensions: Height 700mm, Width 400mm, Depth 350mm
- Warranty: 10 years
- Cost including installation: starting from £2779
Additional key features:
- High-quality stainless steel Inox-Radial heat exchanger
- Environmentally responsible MatriX-Plus cylinder burner which extends the boiler’s service life and reduces CO2 and NOx emissions
- Lambda Pro automatic combustion control for maximum efficiency at all times
- Backlit LCD touch screen display
- Integrated Wi-Fi
- Pressure release valve and condensate combined for easy installation
- Compact design and low weight for installation in a standard kitchen cupboard
- Quiet operation with low fan speed
- Low CO2 emissions for reduced environmental impact
- Modulation range up to 1:10
- Constant temperature control and weather compensated operation (an outside temperature sensor is available for weather compensation)
- Ready for 20% hydrogen mix in the gas supply
- Up to 10 years extended warranty available
- Compatible with Viessmann’s Vitoguide software, and ViStart and ViCare app
- Easy to find spare parts

4. Worcester Bosch Greenstar 2000 30kW (affordable model)
The Worcester Bosch Greenstar 2000 is a highly efficient and reliable boiler with exceptional performance and comfort.
This boiler series offers a range of options to suit different heating and hot water requirements.
One of the key features of the Worcester Bosch 2000 is its compact size, which makes it perfect for flats and homes with limited space. Despite its size, the Worcester Bosch 2000 is a powerful boiler, providing heating and hot water on demand, and it boasts an A-rated efficiency, meaning that it can help to reduce your energy bills.
One of the standout features of the Worcester Bosch 2000 is its high energy efficiency rating, which helps reduce energy consumption and lower heating costs.
The Worcester Bosch 2000 also features intelligent controls, allowing you to easily manage and adjust your heating settings for optimal comfort and convenience.
In addition to its impressive performance, the Worcester Bosch 2000 is known for its reliability and durability. Worcester Bosch has a strong reputation for manufacturing high-quality boilers that are built to last, providing homeowners with peace of mind and long-term value.
Worcester Greenstar 2000 30kW tech spec
- Efficiency: A-rated (93%)
- Suitable for: small and medium homes with one bathroom
- Warranty: 5-year guarantee
- Hot water flow rate: 12 l/pm
- Dimensions: Height 720mm, Width 400mm, Depth 300mm
- Cost including installation: starting from £2269 (the most affordable Worcester Greenstar boiler)

5. Ideal Logic Plus C30 (affordable model)
The Ideal Logic Plus C30 Combi boiler is popular among those looking for a reliable and efficient boiler without breaking the bank.
With its 30kW output, the Logic Plus is suitable for medium to large-sized homes with higher heating demands. It delivers excellent power to ensure a comfortable and consistent supply of hot water and warmth throughout your home. The boiler’s compact size and lightweight design make it easy to install and fit into various spaces, saving valuable space.
Energy efficiency is a key feature of the Ideal Logic Plus 30kW Combi boiler. It boasts a high-efficiency rating, which helps you save money on your heating bills.
The boiler uses advanced condensing technology to maximise heat transfer and minimise wasted energy. Additionally, it features intelligent controls and modulation capabilities that optimise performance and ensure efficient operation.
The Logic Plus 30kW Combi boiler is also known for its reliability and durability. Built with high-quality components and designed for longevity, it offers homeowners peace of mind and hassle-free operation.
This boiler also comes with a lengthy warranty, showcasing the manufacturer’s confidence in its product.
Operating the Ideal Logic Plus is straightforward, thanks to its user-friendly controls and clear display. You can easily adjust settings and monitor the boiler’s performance for optimal comfort and efficiency.
The boiler’s compatibility with smart thermostats and accessories allows additional control and customisation options.
Ideal Logic Plus C30 tech spec
- Energy Efficiency: A-rated (94%)
- Hot water flow rate: 12.4 l/pm
- Dimensions: Height 700mm, Width 390mm, Depth 270mm
- Warranty: 7 years (check out Ideal Logic Plus warranty terms and conditions)
- Cost including installation: starting from £ 2150 (not in stock right now).
Which 30kw combi boiler is best?
Now to the important part, the final verdict! If you’re on a budget, Worcester Bosch Greenstar 2000 30kW Combi is an excellent choice, it’s powerful and has all the Worcester Bosch features that we know and love, the brand is known for its build quality and excellent aftercare should things go wrong.
On the other hand, if you’d like to spend some more to get one of the premium models, the Worcester Bosch Greenstar 8000 Style 30kW Combi is your best bet – with the 8000, you’ll enjoy the exceptional aftercare in addition to the long warranty and the sleek, gorgeous design.
Having said that, all the models we’ve listed about are exceptionally good value and will suit any medium sized home.
And if you’re still in doubt, speak to our friendly customer service on our live chat feature, they will put your mind at ease and answer any lingering questions!