Why choose Worcester Bosch for your next central heating boiler?




Worcester Bosch is the number 1 boiler choice for millions of homeowners, who's focus is on both quality and value for money. Known as the installers choice 9 out of 10 boiler engineers would choose a Worcester Bosch for heating their homes.  

"Which" best buy for 9 years running, scoring top marks for reliability and customer satisfaction 



Worcester Bosch customers have consistently rated 5 stars on Trustpilot

We are Worcester Bosch Accredited Installers

Being accredited installers for Worcester Bosch we are able to offer extended boiler warranties of up to 10 years on every Bosch gas boiler installed by our expert gas boiler engineers.

Worcester Bosch gas boilers are designed and built using only the highest quality and best materials, its no wonder they have been awarded the coveted Which? Best Buy for the last 7 years.

Gasworks are experts when it comes to the Worcester Bosch range of boilers, our close working relationship gives us access to unrivaled product training and support.

This ensures no-one knows Worcester Bosch better than Gasworks.

Worcester Bosch gas boiler 10 Year Guarantee

Up to 10 Year Warranty on every gas boiler installed by Gasworks

WHICH? Best Buy winner for the last 9 Years

Which?best buy gas boiler 2019

Worcester Bosch for peace of mind

Worcester Bosch boilers are built to last, but don't just take our word for it. In a recent Which? survey for gas boiler reliability, Worcester came out as the most reliable gas boiler brand on the market.

Nevertheless if you are experiencing an issue with your Bosch gas boiler, Worcester offer unrivaled support and backup 365 days of the year, this is further backed up by Gasworks.

Benefits of a Worcester Bosch Gas Boiler

• Up to 10 Year Warranty
• 365  Technical Support Helpline
• Which? Best Buy Winner
• Highest Parts and Components
• Best for Reliability

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worcester bosch combi gas boiler system

Worcester Bosch Combination Boilers

A combi or combination boiler is water heater and a central heating boiler in one compact unit. Combination boilers heat the water instantly when a tap or shower outlet is opened, this means you will not need a separate hot water cylinder.Because the hot water is heated as its used and not stored a combination boiler will be more efficient method for heating your hot water.

Advantages of a Worcester Bosch Combi Boiler

No need for a hot water cylinder

Compact and ideal for smaller properties

High pressure water at taps

Instant hot water when needed



Greenstar Combi Boilers 

Combi boilers are a popular boiler solution for both heating and hot water in many smaller homes throughout Ireland. Worcester Bosch was one of the primary leads in the development of the combi boiler in the uk, with their range of Combi Boilers developed to suit virtually every property. 

Convenience and Energy Saving 

The Worcester Bosch Combi boilers have been designed and developed to ensure you get a high preforming boiler that will stand the test of time. Features include a keep hot facility which means hot water is almost instantly available, reducing water run off time at hot water outlets.

This feature is standard in all Worcester Bosch Combi boilers. In Addition to the keep hot facility, each Worcester Bosch Combi boiler will also have an ECO mode facility.

This is activated by pressing the dedicated ECO button on the boiler control panel, this feature will reduce gas usage but will increase water wastage. 

Greenstar CDi Classic 

The top of the range Worcester Bosch Combi Greenstar boiler. These high performing combis are suitable for most small, medium and large homes. This CDi Classic Combi is a wall mounted gas boiler which is known for its superb reliability and efficiency. 

MODEL 29CDi 34CDi 38CDi 42CDi
Hot Water Output 30.9kW 35.0kW 40.0kW 42.0kW
Hot Water Flowrate 12.3ltr/m 14.3ltr/m 16.4ltr/m 17.2ltr/m


High Flow rate of 17.2 ltr/min for larger homes 

Low energy circulating pump  

Includes Frost protection reducing the risk of freezing 

Superb choice of additional controls options 

Industry leader for efficiency 

Greenstar CDi Compact

The smallest worcester bosch combi boiler, its compact design makes it an ideal boiler choice for installation in a standard kitchen cupboard. Despite its compact size, this boiler is capable of providing an excellent hot water delivery for most homes. 


Hot Water Output 28.0kW 32.0kW 36.0kW
Hot Water Flow Rate 11.4ltr/min 13.1ltr/min 14.7ltr/min


High Efficient innovative heat exchanger 

Wide range of control options available 

Easy to use display

Kitchen Cupboard Fit




Worcester Bosch greenstar SI combi boiler

Greenstar Si Compact 

Suitable for small to medium sized homes with one Bathroom, this wall mounted compact boiler can be fitted in a variety of locations.  

HOT WATER FLOW RATE 10.2ltr/min 12.3ltr/min


Frost Protection included 

User Friendly boiler display 

Fits in a standard kitchen cupboard 

Additional control options available 

worcester bosch i combi boiler

Greenstar i

The Greenstar i combi has taken up where the ever popular and reliable i junior has left off. This I junior successor is a superb boiler choice for apartments and homes with no more than 1 bathroom. 

MODEL 25i 30i
Hot Water Output 25.0kW 30.0kW
Hot Water Flow Rate 10.2ltr/min 12.3ltr/min


Easily Adjustable hot water temperature  

Frost Protection 

Energy Efficient 

Wide range of controls available 


greenstar highflow CDi combi boiler

Greenstar HighFlow CDi 

Designed for larger homes with high hot water and heating demands, this boiler is capable of up to 25ltr/min. Enough to comfortably supply continuous hot water to 2 bathrooms. 

Hot Water Output 29.5kW 41.1kW
Hot Water Flow Rate 20.0ltr/min 25.0ltr/min



Fits under a standard kitchen worktop

Wide Range of additional controls available 

Ideal for larger homes 

Frost Protection included

Worcester Bosch Combi Boilers Explained


Worcester Bosch System Boilers

A system gas boiler is the perfect choice for sealed central heating systems. They offer a tidier quicker installation than regular boilers, the main reason for this is the system gas boiler will contain the pump, expansion vessel, safety valve, automatic by pass, and frost protection.

System boilers do not heat the water directly and require a hot water storage cylinder, Solar hot water systems are also compatible with system gas boilers.

Worcester Bosch System Boiler Benefits

Ideal for homes with more than one bathroom

Suitable for small to large properties

Suitable for solar hot water systems

Excellent Control options available


Worcester Bosch - Greenstar i System (9kW to 24kW)  

 The Worcester Bosch I System gas boiler is our most popular gas boiler, it is available in 9KW, 12KW, 15KW, 18KW, 21KW and 24KW outputs, this broad range of outputs makes it an excellent replacement option for the small to medium sized homes. Being a system boiler, it incorporates the circulation pump, expansion vessel and pressure relief valve. All of which are covered during the term of the extended warranty. Warranties range from 7-10 Years depending on installation practices.  

The boiler controls are both simple and easy to use incorporating a digital display screen, additional Worcester control options are available to use with the Greenstar i System boiler range. This allows for better preforming heating system increasing comfort while further reducing operational costs. The low energy circulation pump contained within the boiler, modulates to suit the boiler output this modulation results in reduced electrical usage. 

  • Digital Display 
  • Easy to use Boiler controls 
  • Compatible with Worcester Control Range 
  • 7-10 Year Warranty 
  • Energy Saving Circulation Pump 
  • Which? Best Buy Winner 
  • Reliability Tested 

The most popular gas boiler we install, the system gas boiler range from Worcester Bosch are known for there quality components, engineering and reliability. These gas boilers are robust enough to meet the demands of almost any household. 

Efficient and cost effective 

The Worcester bosch greenstar system gas boilers contain many of the main heating parts, such as the circulation pump. This makes for a much tidier, quicker install and reduced maintenance costs while increasing efficiency. 

Smart Compact Design 

A neat looking boiler that is designed with your home in mind, the Greenstar system boilers space saving design makes them a perfect fit for a range of locations. Need an even smaller sized boiler unit? The system boiler also has a compact range for with a depth of just 270mm! 

Worcester Bosch heating and hot water 

The greenstar range of system boilers are fully compatible with a wide range of additional controls, which will increase your home comfort and efficiency. Take advantage of extended warranties available with the addition of a highly efficient Greenstore hot water cylinder from Worcester Bosch. 

System Boilers can also be used with solar hot water systems. 

worcester bosch i combi boiler

Greenstar i System 

The most popular Worcester Bosch system gas boilers, these boilers can be installed in a wide range of locations. Efficient, reliable and expertly designed this boiler will deliver years of high performance for your home. 

MODEL 9i 12i 15i 18i 21i 24i
Central Heating Output 9.0kW 12.0kW 15.0kW 18.0kW 21.0kW 24.0kW


All major parts are inside the boiler casing 

Suitable for homes with hot water cylinders 

Frost protection included 

Solar Compatible 

Easy to use boiler controls 

Worcester Bosch greenstar SI combi boiler

Greenstar I System Compact 

A smaller wall hung gas boiler, suitable for medium and larger sized homes. This compact boiler is designed to fit in a standard kitchen press, while still incorporating all the benefits of the system gas boiler. 

Central Heating Output 27.0kW 30.0kW


User Friendly Boiler Controls 

Frost Protection included 

Innovative Heat Exchanger 

Will fit in a standard Kitchen cupboard 

Greenstar CDi Classic System 

A wall mounted high preforming and efficient boiler with an excellent reputation for reliability. Compatible with a wide range of controls for an even better performing heating system. 

Central Heating Output 30.0kW 34.0kW


Rapid Hot water Heat up when used with a Greenstore Cylinder 

Industry Leader for Efficiency 

Energy saving pump 

Solar hot water compatible 

Class Leading Worcester Bosch Boiler 

Worcester Bosch System Boilers Explained

Watch The Video

Worcester Bosch System Gas Boiler internal view

Greenstar Regular/Heat Only Boilers

 The Regular gas boiler does not contain the additional components found in both combis and system gas boilers. Such as the circulating pump, pressure relief valve, diverter valves, by pass valves, frost protection to name but a few. 

Small Boiler Size 

Because the regular gas boiler has less components and parts within the boiler casing, it is smaller in length, width and depth. This compact size allows for a neat and tidy looking installation, it will even fit inside your standard kitchen cupboard. 


Designed for small to large sized homes, the Greenstar regular boiler range will improve your homes efficiency and comfort while lowering your carbon output. These robust reliable boilers are also an ideal installation solution when more than one boiler is required to meet the property's heating or hot water needs. 


Worcester Bosch Boiler Range 


Worcester Bosch - Greenstar Ri (12kW to 24kW)                            

The Worcester Bosch Greenstar Ri Condensing gas boiler is a compact heat-only boiler, available for both LPG and Natural Gas and four output sizes 12KW, 15KW, 18KW and 24KW making it an ideal boiler replacement option for small to medium sized homes. The compact size of this gas boiler makes for a comfortable fit in a standard kitchen cupboard. The Boiler also has built in frost protection, providing invaluable frost protection especially in the case of a loft, garage or boiler house installation. The boiler controls are both simple and easy to use, they comprise of a boiler thermostat and on/off switch. This user-friendly gas boiler comes with a 7-year warranty as standard when installed by Gasworks.                                                                                                                                                                       

  • User Friendly Controls 
  • Frost Protection 
  • 7 Year Warranty Bosch 
  • "Which" Best Buy Winner 
  • "A" Rated 
  • LPG and Natural Gas Models 
  • Available in 12KW, 15KW, 18KW and 24KW 

Get A Boiler Replacement Quote Now 

Greenstar CDi Classic Regular 

The top of the range regular gas boiler from Worcester Bosch, these wall mounted boilers are a superb choice for medium to large homes. 

MODEL 30CDi Classic 40CDi Classic
Central Heating Output 30.0kW 40.0kW


Frost Protection included as standard 

Highly Efficient 

Excellent reliability  

High Outputs ideal for large homes

Heat Only gas boiler

Greenstar Ri 27kW and 30kW 

A more budget friendly alternative to the CDi range of regular boilers, the high output Ri range are fully capable of meeting both the space heating and hot water requirements for medium to large sized properties. The compact size allows for a neat installation and despite its high output it will even fit in a standard kitchen cupboard. 

MODEL 27Ri 30Ri
Central Heating Output 27.0kW 30.0kW


Kitchen Cupboard Fit 

Innovative Heat Exchanger 

Additional Control options available 

Heat Only gas boiler

Greenstar Ri 

A neat wall mounted boiler that is ideally suited to small to medium sized homes, the Greenstar Ri boiler is a great boiler replacement option if your current gas boiler is in a kitchen cupboard. 

MODEL 12Ri 15Ri 18Ri 21Ri 24Ri
Output 12.0kW 15.0kW 18.0kW 21.0kW 24.0kW


Kitchen Cupboard fit 

Frost Protection included 

Can be used on open vented systems 

greenstar highflow CDi combi boiler

Greenstar FS CDi regular 

An excellent replacement choice for old floor standing gas boilers. This floor standing regular boiler offers exceptional reliability and heating comfort. 

Output 30.0kW 40.8kW


Condensate pump included 

Frost Protection Included 

High Output to heating and hot water 


      Worcester Bosch Boiler Control Options











Worcester Bosch Controls Explained 

A heating system will typically have some level of control, at the very basic level you would expect a programmer and room thermostat.

Here we briefly explain the different types of controls options available from Worcester Bosch. 




Bosch Easy Control 

Get complete heating control from your smartphone with the EasyControl. An aesthetically pleasing internet connected heating and hot water controller from Bosch. 

Heating Zone Control 

Combine the Bosch EacyControl with Smart TRVs and get total heating control. Control and set different comfort levels for bedrooms, bathrooms, living and kitchen. 

So, if you prefer a cool bedroom at say 16 degrees and a warmer bathroom temperature, simply set the desired temperature levels at the given times. This is very easily done through the Bosch Easy Control app, where you can set several time and temperature controls for each heating control zone. Choose the time, the desired temperature, the day of the week etc. 

Home Presence Detection 

With the Bosch EasyControl, you'll never have to heat an empty house again. Using the latest location technologies, the controller will turn down your heat when you leave the house. This Smart EasyControl from Bosch will even turn your heating back on upon your return. 

Improved Energy Efficiency 

When installed with at least 3 Smart TRVs , the Bosch EasyControl will boost your Homes ErP Rating by 5%. Improving you BER rating and lowering your fuel bills 

  • Intelligent Boiler interaction increasing efficiency 
  • Provides Load Compensation 
  • Provides Weather Compensation 
  • Greater home heating control and comfort 


Complete Boiler Control with Worcester Bosch

Room Thermostat

A room thermostat controls the temperature of air inside the property, enabling you to set the temperature you find most comfortable. 


A programmer allows you to turn your heating on and off at specific times and days, so you can best suit your lifestyle #

Programmable Room Thermostat 

programmable room thermostat is a programmer and room thermostat all in one. This allows you to set desired on/off periods with temperature control. 

Weather Compensation 

Weather compensation is when your boiler will adjust its heat output depending on the current outdoor temperature. The cooler it is outside the higher the boiler output, the hotter the radiators will be. 

Load Compensation 

This feature adjust the boilers heat output depending on the temperature difference between the current indoor temperature and the target temperature. 


Worcester Bosch Comfort programmmer

Greenstar Comfort Plugin Programmer

Easy To Use

7 Day Heating & Hot Water

Programmer Back Lit Display

worcester bosch greenstar sense ii

Greenstar Sense II Weather Compensation

Service Reminder Function

"A+" Rated System

Stylish intelligent control

Worcester Bosch Mechanical Timer

MT10 Plug-in Mechanical Timer


Easy To Use

24 Hour Timer

Straight Forward

Greenstar Comfort II Wireless Programmable Stat

Load Compensation

6 On/Off Periods Per Day

Wireless Installation

Greenstar Comfort Wireless Thermostat RF

Greenstar Comfort RF Wireless Thermostat

Provides Load Compensation

No Wiring Required

Works With 230V Existing Timers/Programmers

Greenstar Sense I Intelligent Room Thermostat

Compatible with 230v timers and programmers

Load Compensation

Increased Efficiency







  25 Year Guarantee On Worcester Bosch Cylinders




  Rapid Heat Up Times

  Energy Efficient

  Excellent Performance



Hot Water Storage Solutions From Worcester Bosch 

If you have or a looking to have, or are looking to install a system or heat only gas boiler. Then you will need a hot water cylinder, the hot water cylinder will provide and store the hot water for usage at the taps and shower outlets.

The hot water cylinder is heated from your central boiler by sending the heated water through the cylinders heat exchanger or coil.  

Enhanced efficiency and performance 

Older cylinders are usually inefficient, they are usually poorly insulated and may have a high level of limescale inside. This build up of limescale will increase hot water heat up times and decrease efficiency.

Even if your insulated cylinder is just over 10 years old it will lose more heat than a modern one, and it may be worthwhile replacing. 

Worcester Bosch Greenstore Pressurised Cylinder 

The Greenstore range of hotwater cyinders are exceptionally high performance cylinders with rapid heat up times and superb efficiency. They come in a wide range of sizes from 90 litres to 300 litres available, you can match your hot water usuage perfectly. 

Designed for use on pressurised water systems, Greenstore cylinders are the perfect choice for pressurised hot water storage. These cylinders can be used with both regular and system gas boilers, and are the perfect partner for the Worcester Bosch System Boilers. So if you would like to benefit from an increased performance, rapid heat up times and increased energy savings, choose a Worcester Bosch Greenstore Cylinder to meet your hot water needs. 

Solar Hot Water Cylinders 

Thinking of adding Solar panels in the future? Why not future proof your hot water system with a solar hot water cylinder from Worcester Bosch. The Greenstore Solar hot water cylinders have been designed for solar hot water heating, with storage capacity's ranging from 150 to 300litres. 


worcester bosch magnetic filter

The Magnetic Filter Range from Worcester Bosch

Over time the water quality in your central heating system can gather harmful deposits and debris. These deposits can affect both the boiler, radiators and all of the heating system components. 


Worcester Bosch Condensing boilers are highly engineered machines designed to operate with good quality water. When the central heating systems water is of a poor quality it can cause blockages and damage to both the boiler and the entire heating system. The efficiency of the heating system will also decrease as well as the lifespan of the boiler. 

Worcester Bosch Boiler Protection 

The Greenstar System Filter from Worcester Bosch will protect your boiler from the damage caused by sludge deposits, maintain efficiency and prolong the boilers lifespan. 

Worcester Bosch 10 YEAR Guarantee

Bosch is a brand renowned for quality, each product from Bosch is manufactured to the highest standards, with intense testing. 

When you purchase a Worcester Bosch boiler from Gasworks you will receive a full parts and labour guarantee for 10 YEARS. 

Worcester Bosch Guarantee Subject to an Annual Boiler Service.