Click Here for The Worcester Bosch Greenstar Heatslave II Prices & Reviews

Worcester Bosch Greenstar Heatslave II: Why choose them? 

It has been quite some time since boilers have become an important appliance in places that have cold climates. They are abundantly used across the UK and you will rarely see a house that doesn’t have a central heating system. It is important to have one as they experience extremely cold weather that can’t be survived without a continuous supply of warmth in the house.

Boilers range from steam, hot water, natural gas, electric, oil to condensing boiler. Each has a distinct characteristic that makes it different from the other. So, it is important to know your own hot water needs before deciding on a boiler.

Combi boilers are a popular name in households. Just as the name suggests, you can use two different types of fuels that you find most conveniently in your surroundings.  There are few other reasons why they are preferred more:

1. Efficiency: They are highly efficient and help in saving gas bills for a long period. You can easily save up a good amount, enough to replace an old boiler by using a combi boiler.

2. Faster: There is no waiting time involved in getting the hot water from the combi boiler. You get it instantly when you need it i.e., on your demand.

3. Compact: They don’t take up a lot of space and are easy to fit wherever you want. This is why it is mostly preferred by small houses as it leaves them with space even after installation.

4. Clean: The water comes clean as the user gets it fresh from the main supply instead of the stored water. This also helps in reducing the chances of the boiler rusting that might happen if the water is stored over a prolonged period.

Worchester bosch is not a new name in the boiler market. It has been around for decades and is one of the topmost boiler manufacturers in the UK. They produce the best in quality, price, and size boilers for different hot water needs. That is one of the reasons why customers prefer them over other brands.

This Worchester bosch green star Heatslave II has three different outputs i.e., 18kW, 25kW & 32kW that are suitable for different houses and needs. They are all efficient and don’t overcharge you for maintenance. You can have a look at the buyer’s guide given below to decide the one that’ll be suitable for you.

Buyer’s guide:

1. Fuel type:

There are four types of fuel that people can use i.e., Natural gas, propane, fuel oil, and electric boiler.

Natural gas is the most used fuel as it is environmentally friendly and also available in most urban areas. It also improves the efficiency of the boiler.

Propane is the second choice and is used in suburban areas. Natural gas and propane are usually used in combi boilers as one doesn’t need a conversion kit for the process.

Fuel oil and electric boilers are next in line if the first two options aren’t feasible by the users. Electric ones are a cheaper option for boiler; however, they are more suitable for easy heating jobs. Fuel oil is common in rural areas where wood and other such sources of energy are used.

Each of these fuel types requires a different amount of money to be spent on them, so choose what you can pay for.

2. Venting:

Having an outlet for gases is another important thing that one needs to consider before purchasing a boiler. There are three types of boilers depending upon the types of vent used by them: chimney vented, power vented, and direct vent boilers.

Chimney vented boilers are connected to the chimneys via which they let the gases out. Always ensure that the chimney is cleaned before connecting it, otherwise, it might be harmful.

Power vented boilers are also known as direct exhaust boilers as they use in-built blowers to let the gases out. Instead of chimneys, they make use of sidewalls and chimneys for the purpose.

Direct vented boilers are the ones that are used in urban households in today’s time. You don’t need a chimney or anything as it goes best for sealed houses.

3. Efficiency

The efficiency of a boiler indicates how well is your boiler going to use gas. It directly has an impact on the money you will have to spend on your boiler. So, always go for a boiler that has higher efficiency ratings. A boiler with 90% and above efficiency will always provide you with the best results.

Anything lower than this might come cheaper but in the long run, you’ll have to spend more money on its repair and other services.

4. Heating controls

There are new and modern types of boilers that have different controls. Whatever you choose, it should be convenient for you to use. For example, there are now smart controls that allow you to connect the boiler with your smartphone and control it. However, if you are someone who isn’t tech-savvy, then you can go ahead with a boiler that has normal controls.

5. Size

The size of the boiler matters a lot. You don’t want to purchase something that will look too big in your house. So always have a professional inspection as they’ll be able to guide you better regarding the boiler that will suit your house the most.

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This boiler from Worcestershire is one of the highest-rated oil combi boilers in the market. It is a great option for families with young children as the controls are concealed and hence not easily visible. Apart from that, it offers high efficiency and has several other heating controls especially for the user’s comfort.


  • This boiler is highly efficient.
  • It is safe for families with young children.
  • It is designed to provide maximum comfort to the users.


  • It is a bit pricey.


  • This boiler has been been given a SEDBUK efficiency rating of 90% and also A-rated for heat while B for water. It uses the water heated by green sources that include solar energy and wood-fired boilers to achieve the highest level of efficiency that it has to offer.
  • It has an energy-saving ECO mode that helps in cooling down the burner before reheating again.
  • The in-built frost protection ensures that the boiler remains damage-free.
  • You can easily program your heating needs throughout the week with the help of an optional programmer via which you can control the central heating.
  • There is another ‘keep hot’ facility in this boiler that has an inbuilt thermal store and it provides its users instant hot water to meet their demands.

Product specifications:

  • Dimensions: 855 x 520 x 600 mm
  • Output: 18
  • Flow rate: 15
  • Efficiency: 90%
  • Price: 2256


Known for high-efficiency, this boiler is preferred among consumers for several other reasons too. It has inbuilt frost protection, concealed controls and is always ready to provide instant hot water access to the users.



  • You can count on the efficiency of the boiler.
  • The concealed controls ensure the safety of young children.
  • It keeps the user’s comfort as a priority and sets the temperature accordingly.


  • It is a bit pricey.


  • SEDBUK has rated this boiler as A for its heat while B for water and it also has an efficiency rating of 90%. Since it uses green sources to generate heat, it helps in improving the efficiency of the boiler even further.
  • The energy-saving ECO mode helps in cooling the burner before reheating it again. This reduces wastage of energy.
  • It also features built-in frost protection to help save the machine from frost damage during extreme cold.
  • It has another feature that allows the users to program their weekly heating needs and get the water accordingly.
  • Its in-built thermal store keeps the water always hot and instantly ready for discharge to the users.

Product specifications:

  • Dimensions: 855 x 520 x 600 mm
  • Output: 25
  • Flow rate: 18
  • Efficiency: 90%
  • Price: 2353


There are several features that this boiler boasts of which have made it a favorite among the consumers. It has excellent heating controls, is highly-efficient, and protects itself from frost in extreme winter when the boiler is most in use.



  • It helps in saving money on gas bills due to its efficiency.
  • It is safe to use.
  • Several controls work in the favor of the user’s comfort.


  • It is a bit pricey.


  • This boiler has a high-efficiency rating of 90% and another rating of A for its heat & B for its boiler from standard rating SEDBUK. It has other controls that help in optimizing energy use and make it even more efficient.
  • Its ECO mode helps in saving energy as it cools down the burner before reheating it.
  • There is in-built frost protection to keep it away from frost damage in winters.
  • You can program your weekly water heating needs at once and get a steady supply of water the following week with ease. This is another way of improving efficiency and reducing energy waste.
  • There is an in-built thermal store that aims at keeping the water always hot and instantly ready.

Product specifications:

  • Dimensions: 855 x 520 x 600 mm
  • Output: 32
  • Flow rate: 22
  • Efficiency: 90%
  • Price: 2520

What Do Industry Experts Have To Say?

Experts have been in favor of this product from Worcester bosch for several reasons. This Greenstar heat slave boiler is a highly efficient boiler that provides its users with a quality water heating solution. It a high-performing combi boiler that works well even with larger households that use multiple bathrooms because of its high output. This was earlier an issue with combi boilers as they supply water from the mains which led to pressure reduction if multiple taps were used simultaneously. But not with this boiler.

This boiler also has concealed controls that help the users in keeping the youngsters in their household safe, in case they try to fidget with the controls. Most households have young children and having concealed controls have proved to a boon for many people. Also, the controls are clear to the users due to its backlit display so they don’t any issues in understanding it.

While we know of its efficiency, there is another feature that makes this product even better. It makes use of renewable resources for heating water. It also features a pre-heated thermal store that provides instant hot water on demand. This helps in saving energy and ultimately helps in cutting costs as well making it environmentally as well pocket friendly for the users.

How Do We Decide On These Products For You?

There are several factors taken into consideration before we suggest a product to our customers. We have thorough research and survey regarding the benefits and uses of the product and only after we received satisfied reviews from customers, did we finally decided on these boilers from Worcester bosch for you.

In our preliminary research, we found that people praised this boiler for its high-efficiency ratings. Since we know there are several other boilers giving competition to this one based on efficiency ratings, we dug a bit deeper. There, we found out the real reasons why this boiler is way different from other such boilers in the market.

Apart from high-efficiency, these boilers aim at using environmentally friendly resources to heat water so that less emission is caused during the process. If you use it with a thermostat, you can make this boiler even more comfortable for your use.

It also has in-built frost protection that helps in keeping it safe from extreme cold. It is also easy to service and maintains, not much hassle is required in the process.

Households with kids preferred it the most due to its concealed controls.

Overall, this boiler had several positive reviews that lead to this conclusion that people looking for a good combi-boiler, should opt for this.

FAQs About Combi Boiler:

  • What sized boiler will be right for my house?

It depends on the space you have and also your hot water needs. Get a boiler with more output if you have more people in your house, otherwise, you can opt for a lesser output boiler.

  • How often should I service my boiler?

You should have your boiler serviced on an annual basis. It helps in keeping the boiler damage free.

  • How many years warranty is offered by the company?

This boiler has a warranty period of 2 years.

  • How often should I replace my boiler?

If the damage to the boiler can be fixed, don’t replace it. Only replace a boiler if it seems to longer fit for use.

  • Are combi boilers energy efficient?

Combi boilers are known for their high-efficiency ratings and thus preferred over other boilers. these boilers have additional controls too that further helps in improving the efficiency ratings.

Did you know?

Here are some interesting facts about Worcester bosch:

  • Worcester bosch started its operation in 1962 but as Worcester heating that supplied oil-fried central heating equipment across the country.
  • It was in the 1970s when combi boiler was first introduced in the UK and people started preferring gas boilers over oil, that Worcester began manufacturing different boilers than the conventional ones that were already in use.
  • Through the 1970s and 80s, Worcester kept growing and was known for producing quality combi boilers.
  • It was in the 1990s that it joined hands with the bosch group to become Worcester bosch and since then they have worked as a single unit to produce environmentally friendly heating equipment for its users.

Stories from real-world use cases:

Source: Trustpilot

1. Kate stevens

Worcester boiler review

I have had my Worcester boiler for nearly a year now and I will be getting it serviced in February. It did break down a day after installation and a Worcester engineer came out to fix it. The local plumbing service that I used to install the boiler was on hand to learn about the fault for future reference.
Since then it has not been a problem and I have subsequently been pleased with the boiler.

2. Peter Nicholson

Excellent boiler and first-class…

Excellent boiler and first-class friendly service.

3. Mr. Hodgkinson

Simply the best

Boiler developed an AAV problem – response time was superb and the matter was completely resolved within 48 hours of it being reported.
Well done Worcester Bosch.

4. Mr. Mathinus

Excellent boiler

The excellent boiler had it for a year now and not once had a cut-out. Still under warranty but very happy so far.

5. Mr. Kumar

first time got WORCESTER BOSCH…

The first time got WORCESTER BOSCH installed in my house and I am very pleased with it so far very quiet hardly hear a noise greatly running its been nearly a year. Doesn’t long to heat the whole house greatly. I am glad I got Worcester this time. The installer was very professional and a very clean job finished within time.

6. Anonymous

Good boiler

I had a Worcester Bosch Greenstar boiler installed a year ago and very happy with it. Quiet and efficient, so much so that my gas supplier asked me if I was sure about my meter reading as it showed much lower usage than previously. Easy to use, paired with a Hive system. Hassle-free and with a long warranty. Very happy.

7. Brian Thurtle

New Boiler new comfort level

Our old boiler was taking ages to get warmed up and the pump was getting noisy. We accepted our builders’ advice to go with the new boiler and the difference was immediate. Much quieter and all rads were hot within 20 minutes. Time will tell how it performs in the long run but as we used a registered installer and bought Worcester filter equipment we consequently got a 12-year guarantee. Fingers crossed for a long and trouble-free boiler life.


Worcester bosch has been a leading name in the boilers industry. It has a proven track record of catering to the needs of its customers and manufacturing products accordingly.

These Greenstar Heatslave II boilers have the best features available that make them the most suitable combi boilers.

It is highly efficient and helps in saving a lot of money on gas bills. In addition to this, it has several other controls that help in improving its efficiency while maintaining the comfort level of the users.

There are three different output levels for different hot water needs. If you have a small household, opt for an 18kW output boiler. Similarly, 25kW & 32kW output boilers are suitable for medium and large-sized households respectively.

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