🕑 10 minutes read
[A Comprehensive Review]

Introducing the Worcester 4000, the latest iteration of the UK's most commonly installed boiler model. Succeeding the Greenstar i model, the Worcester Bosch 4000 boiler series stands out as one of the top choices in the current boiler market, boasting exceptional reliability, warranty coverage, pricing, and performance.

Moreover, this new model is packed with state-of-the-art technology, a sleek design, and a compact size; it's set to become Worcester Bosch's hottest seller yet!

“After years of leading the way in the industry, Worcester Bosch has launched its latest and greatest boiler lineup, Greenstar 4000 series in 2021!”

Let's discuss the details of the brand-new hydrogen-ready Worcester Bosch Greenstar 4000 and address key considerations for those in the market for a new boiler.

[Experts Insights]
Worcester Bosch Greenstar 4000 Series: A Game-Changer In The World Of Boilers!

Worcester Bosch Greenstar 4000 boiler  image

Being the latest addition to the esteemed Worcester Bosch boiler family, the Worcester Bosch Greenstar 4000 range is designed to exceed customers' expectations. This revolutionary boiler series builds upon its predecessor's success, offering enhanced features tailored to meet the heating needs of small to medium-sized homes across the UK.

Does The Worcester Greenstar 4000 Work With Hydrogen?

Yes, it does!
This boiler has a sleek wall-mounted design and is ready to use with hydrogen, showing Worcester-Bosch's dedication to cutting-edge home heating solutions.

Is The Worcester Greenstar 4000 The Right Boiler For Your Home's Heating?

Regarded as a market leader, the Worcester Greenstar 4000 is the successor to the highly popular Greenstar i and stands as the contemporary option for UK households. Not only does this boiler take the crown for being extensively installed across the nation, but it also boasts a reputation for unparalleled reliability.

The Worcester Bosch 4000 represents a culmination of efficiency, competitive pricing, and impressive warranty options, making it an optimal choice for homeowners seeking an effective heating solution. Its performance in heating and hot water outputs is exceptional, catering to a wide range of domestic requirements.

Why Is Worcester Bosch Greenstar 4000 Good?

Worcester Bosch Greenstar 4000 is designed to surpass its predecessor; it offers enhanced features suitable for most small- to medium-sized homes in the UK. Despite its updated appearance, internal components remain consistent with previous Greenstar models.

Specifications of Worcester Bosch Greenstar 4000 Boiler:

  • Operates on natural gas.
  • Positioned as a mid-range boiler model.
  • Hydrogen blend ready, ensuring adaptability to future energy trends.
  • Engineered for quieter operation, minimising noise disturbance.
  • Compatible with a range of Worcester Bosch controls and smart products, including Nest, tado, and Hive.
  • Ideal choice for small to medium-sized residences.
  • Facilitates easy servicing with removable side panels for maintenance access.
  • Offers a maximum of a 10-year guarantee for added peace of mind.
  • Boasts an ErP rating of 94%, earning an A-rated efficiency certification.
  • Dimensions measure 710 x 400 x 310, ensuring suitability for various installation spaces.

When considering a combi boiler for smaller homes with a single bathroom, the Worcester Greenstar 4000 proves to be an excellent choice, providing instantaneous hot water supply.

Worcester Bosch Greenstar 4000 boiler range is an A-rating boiler for both hot water and heat.

Featuring two distinct power outputs, the Greenstar 4000 offers versatility, catering to a wider range of UK households. It's worth noting that this boiler is suitable for placement in kitchen cupboards, but precise measurements are recommended for a perfect fit.

Worcester Bosch Greenstar 4000 25kW

The Worcester Greenstar 4000 25kW model is particularly perfect for smaller homes with up to 10 radiators, offering a flow rate of 10.5l/min and a heat output of 25kW. However, upgrading to the 30kW version is recommended for homes with two bathrooms to meet higher hot water demands.

Worcester Greenstar 4000 25Kw Combi Boiler

Worcester Bosch Greenstar 4000 25kW

Considering the popularity of the Worcester Bosch Greenstar 4000 - 25kW version, it's advisable to schedule installation during the warmer months when demand and prices are lower.

Worcester Bosch Greenstar 4000 30kW

On the other hand, the Worcester Greenstar 4000 30kW combi boiler is suitable for small to medium-sized homes with up to 16 radiators.

Worcester Bosch Greenstar 4000 30kW

Greenstar 4000 30kw Combi Boiler - Standard Flue

With its higher power output, the WB Greenstar 4000 model boasts a flow rate of up to 12.3l/min, making it suitable for homes with two bathrooms and higher hot water demands.

The Worcester Greenstar 4000 series provides efficient heating solutions for compact spaces, allowing homeowners to choose the model that best suits their needs.

Key Features of the Worcester Greenstar 4000 Combi Boiler

Exceptionally Efficient Performance

The Worcester Greenstar 4000 has an ErP A-rating for heating and hot water, delivering outstanding energy efficiency. Its ability to modulate its power output from 4.8kW to a robust 30kW ensures you only use the amount of energy necessary, optimising fuel consumption and reducing energy bills.

Engineered for optimal energy performance, the Greenstar 4000 boasts impressive energy efficiency ratings, ensuring reduced environmental impact and lower energy bills for homeowners.

Enhanced Technology

The Greenstar 4000 is equipped with advanced technology, including a modulation ratio of 1:10, allowing for precise output adjustment to match varying heating demands. This intelligent feature minimises energy wastage and maximises efficiency.

Whisper-Quiet Operation

This innovative boiler is one of the quietest in its category, 45dB(A), having gained Quiet Mark approval. Such recognition guarantees the Greenstar 4000 will operate with minimal noise disturbance, perfect for quiet homes or nocturnal operations. Whether you're relaxing in your living room or sleeping soundly at night, the Greenstar 4000 offers a serene heating experience that won't disturb your peace and quiet.

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Easy Installation and Maintenance

Worcester Bosch boilers are renowned for their user-friendly design, and the Greenstar 4000 is no exception. With simplified installation procedures and easy-to-access components, servicing and maintenance are hassle-free.

Smart Connectivity

In an era where convenience is king, the Worcester Greenstar 4000 emerges triumphant, offering compatibility with smart thermostats. This functionality facilitates temperature management from your smartphone or tablet, delivering ultimate comfort and control over your home's climate.


So homeowners can stay in control of their heating system with built-in Wi-Fi connectivity. Compatible with Bosch EasyControl and smart thermostatic radiator valves, the Greenstar 4000 offers convenient remote operation and energy usage tracking.

Eco-Friendly Packaging

Worcester Bosch demonstrates its commitment to sustainability with 99.9% recyclable product packaging, minimising environmental impact and promoting responsible consumption.

Intelligent Filling System

Next-generation intelligent hot water capability automatically adjusts to deliver the precise amount of hot water needed, even in multiple tap usage, ensuring you're met with unwavering water temperature and volume without delay.

Keep your boiler pressure at optimal levels with the intelligent filling system, ensuring efficient operation and alerting you to any potential issues.

User-Friendly Interface Worcester-Bosch-Greenstar-4000-boiler-PCB

A comprehensible LCD display makes for straightforward operation, simplifying programming and troubleshooting. The intuitive controls permit effortless adjustments to both heating and hot water to suit your living preferences, offering ease and accessibility for all family members regardless of technical abilities.

Proven Durability

Built with high-grade components and backed by Worcester Bosch's outstanding reputation for quality, the Greenstar 4000 boasts reliability in its lifecycle, promising homeowners peace of mind with a product that's built to last.

Homeowners can rest assured with this long-lasting product, backed by a standard guarantee of 7 years. Opting for the Greenstar System Filter extends the guarantee to 8 years while adding about £40 for non-WAI Excelerate members, resulting in a 10-year guarantee.

Perfect heating solution for a compact place

If you're living in a cosy space with just one bathroom, choosing the right combi boiler can make all the difference. The trick is to find one that delivers hot water on demand without missing a beat.

Enter the Greenstar 4000 - a versatile beast with a choice of power outputs that cater to a wide array of UK homes, small or big. This boiler is absolutely up to the task!

Wondering if it'll squeeze into your kitchen cupboard? It's a common concern, but here's the good news: the Greenstar 4000 is designed to fit neatly into most kitchen configurations. That said, always measure your space to ensure a picture-perfect installation.

Choose the Greenstar 4000 for effortless efficiency in smaller homes. It's the professional's choice for a seamless blend of performance and convenience.

Not suitable for larger homes

The Worcester Bosch Combi Greenstar 4000 is not suitable for heating large homes with more than two bathrooms or ten radiators.

What is the ErP rating of Worcester Bosch 4000?

The ErP rating, which stands for ‘Energy Related Products Directive’, was established by the EU to eliminate inefficient household appliances. This directive aims to simplify the identification of energy-efficient products, leading to reduced carbon emissions and potential savings on energy costs.


Boilers are required to display their certified efficiency level, ranging from G (the lowest) to A+++ (the highest). As part of the ErP directive, manufacturers must adhere to Ecodesign regulations, ensuring that heating systems meet specified standards. This initiative prompts the phasing out of heating systems that fail to meet these requirements, encouraging the use of greener and more eco-friendly choices.

All models within the Worcester Bosch 4000 range, including both system and combi boilers, proudly achieve an ErP rating of 'A'.

Greenstar 4000 Boiler Features

Simple Switch

Seamless boiler replacement for select Worcester Bosch models, minimising installation time and costs.

Quick Tap

It has an instant tap function for hot water delivery, reducing wait times and water wastage. Energy Efficiency

A-rated efficiency certification offers significant energy savings and reduced carbon emissions.

Quiet Operation

Operates at low noise levels, ensuring a peaceful heating environment.

Smart Connectivity

Compatible with leading smart home devices, providing remote control and energy usage insights.

Intelligent Filling System

Maintains optimal boiler pressure levels, enhancing system performance and reliability.

Worcester Bosch Greenstar 4000 Boiler Prices

Boiler Type Cost
System Boilers
Worcester Bosch Greenstar 4000 12 kW £1,100
Worcester Bosch Greenstar 4000 15 kW £1,150
Worcester Bosch Greenstar 4000 18 kW £1,200
Worcester Bosch Greenstar 4000 21 kW £1,250
Worcester Bosch Greenstar 4000 24 kW £1,300
Combi Boilers
Worcester Bosch Greenstar 4000 25 kW £1,250
Worcester Bosch Greenstar 4000 30 kW £1,350

The Worcester Bosch Greenstar 4000 is a testament to innovation and quality in the heating industry. With its cutting-edge features, superior efficiency, and user-friendly design, this boiler series sets a new standard for home heating solutions. Whether you're upgrading your existing system or installing a new boiler, the Greenstar 4000 offers unmatched performance and peace of mind.

Professional Boiler Installation in London

Experience the future of heating with the Worcester Bosch Greenstar 4000. If you need any support choosing the right boiler type for your home needs, call serviceteam professional gas safe engineers.

Serviceteam is an accredited Worcester Bosch Installer in London.

accredited Worcester Bosch Installer

Schedule a professional boiler installation today with serviceteam and enjoy reliable, efficient, and eco-friendly heating for years.