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Worcester Bosch Greenstar Heatslave II 18/25 boiler

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Plumbproud rating

76.12%

Worcester Bosch Greenstar Heatslave II 18/25 Combi Oil boiler

We score each boiler we sell by considering a number of different factors including price installed, manufacturer guarantees, energy efficiency, the likely cost of running, and more. For this Worcester Bosch Greenstar Heatslave II 18/25 Combi boiler, we have awarded a rating of 76.12%.

You should budget around £3,500 for the supply and installation of this Worcester Bosch Greenstar Heatslave II 18/25 Combi boiler by PlumbProud.

You can get more information and a free quote for the Worcester Bosch Greenstar Heatslave II 18/25 boiler by entering your postcode in the quote boxes on this page, clicking here to email us, or by giving us a call on 01604 343053.


Installed price around

£3,500

GET A COMPETITIVE BOILER QUOTE

Please enter your postcode below to get a personalised quotation for the perfect boiler for your home

Worcester Bosch Greenstar Heatslave II 18/25 Combi Oil boiler frequently asked questions

What type of boiler is the Worcester Bosch Greenstar Heatslave II 18/25?

Worcester Bosch’s Greenstar Heatslave II 18/25 is one you might consider if you’re looking for a combi boiler for your house or flat.

In many properties, combi boilers are more suitable than traditional types of boiler. Combi boilers heat water instantly on demand, which they draw directly from the mains supply, removing the need for storage tanks that can take up valuable space in your home.

A combi boiler is often the right choice for a smaller property, particularly if your home doesn't have a useable loft. As water is heated and delivered immediately rather than being kept warm for hours in an immersion tank, combi boilers reduce oil usage, thereby minimising your heating costs.

The main disadvantage of combi boilers is that they can only heat a certain amount of water at any one time. This means that, if two people are using different taps or showers within your home at the same time, the flow of heated water to each will be reduced, as will the water pressure and temperature.

Is the Worcester Bosch Greenstar Heatslave II 18/25 combi boiler suitable for my house or apartment?

Selecting the right boiler for your home means choosing a boiler that is the right size. And, by size, we don't mean how big it is, we mean how powerful it is - the "output".

Your boiler’s output is a measurement of the power it has available to it to heat the water you need for your radiators or for when you turn on a tap, bath or shower. A higher output rate means it has more power and can heat more water.

It's important to choose an output that matches the demand for water in your home because if your boiler has too low an output, you'll often find only lukewarm water comes out of your taps or heats your radiators. If it’s too high, you’ll be paying more for your oil than you need to.

The Worcester Bosch Greenstar Heatslave II 18/25 combi has an output of 25 kW, so which types of property would this Worcester Bosch Greenstar Heatslave II 18/25 Combi boiler be appropriate for?

Most Gas Safe engineers would suggest that the most suitable type of property for installing a Worcester Bosch Greenstar Heatslave II 18/25 combi boiler would be smaller homes and apartments with up to 10 radiators and one bathroom.

Flow rates are important when choosing a combi boiler as well as output rates.

A combi boiler's flow rate (measured in litres per minute) describes how much water it can instantly heat then distribute to the taps and radiators in your home - you will need to factor this into your decision on a new combi boiler. This Worcester Bosch Greenstar Heatslave II 18/25 Combi boiler's flow rate is 18 L/m.

If you have a lot of radiators and bathrooms in your home and there's lots of demand within your household for hot water at the same time (like morning or evening showers and baths), you'll need a boiler with a high flow rate.

However, it's not quite that simple. If your local mains water pressure is low, you're not going to gain any benefit from choosing a combi boiler with a high flow rate because that higher flow rate doesn't mean it can draw more water from the mains pipes.
When our engineer comes out to quote you, they may recommend that you choose a heat only boiler or system boiler instead if your family's demand for hot water is higher than normal.


What are the dimensions of the Worcester Bosch Greenstar Heatslave II 18/25 boiler?

The Worcester Bosch Greenstar Heatslave II 18/25 measures 855 mm in height by 520 mm in width by 600 mm in depth.

Floor-standing boilers can still be found in hundreds of thousands of properties in the UK - however, many homeowners are considering switching to wall-mounted units to create new living space for themselves and their families. Our engineers can replace your current floor-standing unit with a wall-mounted model, although please be aware that we may need to charge more if your current pipework needs replacing.

Your investment will be worth it as you'll more than cover the cost with the saving you make every year on your oil bills.

If you are considering replacing your current heat only or system boiler with the Worcester Bosch Greenstar Heatslave II 18/25, please be aware that this will involve removing your hot water cylinder and/or expansion tank.

For guidance and further information, please contact the team at PlumbProud who will be happy to help you make the right choice.

Worcester Bosch Greenstar Heatslave II 18/25 – condensing or non-condensing?

The Worcester Bosch Greenstar Heatslave II 18/25 is a condensing oil boiler - in fact, we recommend that you select this model or one of the latest condensing boilers on the market as the technology continues to improve over time.

Condensing boilers capture the heat still present in the flue exhaust gases and water vapour condensation created when the oil is burned and they recycle this back into the heating system to warm up the cold water re-entering the boiler from your radiators.

They're much more environmentally friendly and installing one results in much lower annual oil bills.

How energy efficient is the Worcester Bosch Greenstar Heatslave II 18/25 combi?

With more and more of us concerned about environmental issues and climate change, how we heat our homes has become an important issue to many homeowners.

We generate 14% of UK greenhouse gas emissions through centrally heating our domestic properties. Gas boilers are mainly responsible for harmful nitrogen dioxide emissions in larger British cities.

Will installing a Worcester Bosch Greenstar Heatslave II 18/25 combi be a positive contribution to the environment? Let's see what the experts say.

Boilers manufactured or supplied to UK domestic properties must achieve a legal minimum energy efficiency rating of 92% (equivalent to a good "A" grade using the SEDBUK scale). Prior to this, the minimum was 88% (88% and 89% are a "B" SEDBUK grade and anything 90% or above is an "A" grade).

The energy efficiency rating of a boiler refers to the amount of energy it uses to perform its everyday functions as well as the amount of energy it wastes.

The Worcester Bosch Greenstar Heatslave II 18/25 has been given a rating of 90% for energy efficiency, equivalent to a SEDBUK "A" rating.

The Energy Related Products Directive (ERP) was introduced in 2015 and it applies to all products that consume energy throughout their lifetime, including during the manufacturing process and at the point of final disposal.

The purpose of the ERP is to ensure that companies create products that are kinder to the environment by reducing both the energy they use and the harmful emissions they produce.

The Worcester Bosch Greenstar Heatslave II 18/25 has an ERP rating of "A" for heat and "B" for hot water production.

Is this Worcester Bosch Greenstar Heatslave II 18/25 combi covered by a warranty?

A parts and labour warranty of 2 years is included when you purchase the Worcester Bosch Greenstar Heatslave II 18/25 boiler through PlumbProud.


Worcester Bosch Greenstar Heatslave II 18/25 Oil Combi boiler specifications

Powered by GasOil
LocationExternal
Condensing?Yes
Efficiency rating90%
Band ratingA
LPG Compatible?No
P/L Warranty2 Years
Output in kW25 kW
Height855 mm
Width520 mm
Depth600 mm
MountingFloor
Flow rate18 L/m
ERP HeatA
ERP WaterB

The top 10 rated Oil Combi boilers

Using the Plumbproud scoring system, the current 10 ten Oil Combi boilers assessed using a number of important variables are as follows:

1Worcester Bosch Greenstar Heatslave II 12/1876.19%
2Worcester Bosch Greenstar Heatslave II 18/2576.12%
3Worcester Bosch Greenstar Heatslave II External 12/1875.95%
4Worcester Bosch Greenstar Heatslave II 25/3275.83%
5Worcester Bosch Greenstar Heatslave II External 25/3275.58%
6Grant Vortex Pro 2167.46%
7Grant Vortex Pro 2667.43%
8Grant Vortex Pro 26kW67.35%
9Grant Vortex Pro 2167.31%
10Grant Vortex Pro 2667.14%

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Worcester Bosch Greenstar Heatslave II 18/25 boiler

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Worcester Bosch Greenstar Heatslave II 18/25 Combi Oil boiler

  1. Home
  2. Worcester Bosch Greenstar Heatslave II 18/25
Plumbproud rating for this boiler
76.12%

We score this Worcester Bosch Greenstar Heatslave II 18/25 Combi boiler as 76.12% on the PlumbProud quality scoring system. Our rating is based on various factors, including the installation price, the length of the manufacturer's warranty, and the expected energy efficiency and operating costs.

We estimate that this Worcester Bosch Greenstar Heatslave II 18/25 Combi boiler will cost £3,500 fully installed through PlumbProud provided that the fit is straightforward.

You can get more information and a free quote for the Worcester Bosch Greenstar Heatslave II 18/25 boiler by entering your postcode in the quote boxes on this page, clicking here to email us, or by giving us a call on 01604 343053.


Installed price guideline
£3,500

Get your free quote

Worcester Bosch Greenstar Heatslave II 18/25 Oil Combi boiler specifications

Powered by GasOil
LocationExternal
Condensing?Yes
Efficiency rating90%
Band ratingA
LPG Compatible?No
P/L Warranty2 Years
Output in kW25 kW
Height855 mm
Width520 mm
Depth600 mm
MountingFloor
Flow rate18 L/m
ERP HeatA
ERP WaterB

Worcester Bosch Greenstar Heatslave II 18/25 Combi Oil boiler frequently asked questions

Worcester Bosch Greenstar Heatslave II 18/25 - combi, system or regular boiler?

If you’re looking for a combi boiler for your house or flat, you may wish to the consider the Worcester Bosch Greenstar Heatslave II 18/25.

Traditional boilers consist of one or more large tanks that take up a lot of space in people's homes. One tank heats water and keeps it warm and the other stores water for heating later.

In contrast, a combi boiler is a much smaller stand-alone unit. Instead of requiring water tanks, it draws cold water from the mains. When hot water is needed for a shower, for the washing up, or the dishwasher, the cold water is heated instantly by the boiler and distributed to where it is needed.

The main disadvantage of combi boilers is that there is a limit to how much water they are capable of heating at the same time. For instance, water pressure, volume and temperature will be adversely affected if more than one individual in the home needs hot water at the same time.

Is a Worcester Bosch Greenstar Heatslave II 18/25 combi boiler suitable for my apartment or house?

You should make sure that the boiler you choose for your property is the right "size". And size doesn't mean its physical dimensions. Size means how much power it has - the "output".

A boiler's output level measures how much power it can use to provide you with the hot water you need for your radiators and taps. If a boiler has a high output rate, it can heat greater volumes of water.

If you choose a boiler with too low an output, you'll find that the water coming out of your taps and in your radiators won't be as hot as you want it to be. Choosing one whose output is too high means you'll pay more than you need to for the oil your boiler needs to work.

The Worcester Bosch Greenstar Heatslave II 18/25 combi outputs at a maximum of 25 kW, so which types of property would this Worcester Bosch Greenstar Heatslave II 18/25 Combi boiler be appropriate for?

Most Gas Safe engineers would suggest that the most suitable type of property for installing a Worcester Bosch Greenstar Heatslave II 18/25 combi boiler would be smaller homes and apartments with up to 10 radiators and one bathroom.

With combi boilers, flow rates are as important a consideration as output rates.

All combi boilers draw water from the mains. They then heat this water instantly whenever it's needed and distribute it to your radiators and taps.

A boiler's "flow rate" describes how much water a boiler can draw from the mains at any one time, which it then heats and sends around your home (measured in litres per minute). This Worcester Bosch Greenstar Heatslave II 18/25 Combi boiler's flow rate is 18 L/m.

If your home has a large number of radiators, a lot of bathrooms, or multiple people who wish to use the hot water at the same time, your combi boiler may not be able to draw as much water from the mains as it needs to serve everyone, regardless of how high the flow rate is.

When our engineer comes out to quote you, they may recommend that you choose a heat only boiler or system boiler instead if your family's demand for hot water is higher than normal.


How large is the Worcester Bosch Greenstar Heatslave II 18/25?

The Worcester Bosch Greenstar Heatslave II 18/25 measures 855 mm high and 520 mm wide by a depth of 600 mm.

Many homes in the UK still have floor-standing boilers like the Worcester Bosch Greenstar Heatslave II 18/25, even though wall-hung boilers have become the product of choice for most homeowners over the last 20 years. If you'd like to replace your existing floor-standing boiler with a compact, wall-mounted boiler to create more space for you and your family, please bear in mind that your pipework may need to be replaced in addition to the cost of the boiler and its installation.

Savings on your oil bills will eventually completely pay for the one-time investment but it will take a few years.

Replacing an existing heat only or system boiler with the Worcester Bosch Greenstar Heatslave II 18/25 will also require our fitters to remove and dispose of your hot water cylinder/expansion tank.

Please contact PlumbProud for more information and guidance on the right course of action for you.

Greenstar Heatslave II 18/25 – non-condensing or condensing?

The Worcester Bosch Greenstar Heatslave II 18/25 is a condensing oil boiler - in fact, we recommend that you select this model or one of the latest condensing boilers on the market as the technology continues to improve over time.

Condensing boilers capture the heat still present in the flue exhaust gases and water vapour condensation created when the oil is burned and they recycle this back into the heating system to warm up the cold water re-entering the boiler from your radiators.

They're much more environmentally friendly and installing one results in much lower annual oil bills.

Is the Worcester Bosch Greenstar Heatslave II 18/25 combi considered environmentally friendly?

More and more homeowners are aware of the importance of how we heat our homes and its impact on climate change and other environmental issues.

The power we need for our central heating systems accounts for around 14% of the UK’s greenhouse gas production. There are often dangerous levels of ambient nitrogen dioxide gases in the atmospheres of British cities because of our use of gas boilers.

Is the Worcester Bosch Greenstar Heatslave II 18/25 combi an environmentally friendly choice for your home? Let’s have a look at the figures.

Boilers manufactured or supplied to UK domestic properties must achieve a legal minimum energy efficiency rating of 92% (equivalent to a good "A" grade using the SEDBUK scale). Prior to this, the minimum was 88% (88% and 89% are a "B" SEDBUK grade and anything 90% or above is an "A" grade).

The energy efficiency rating of a boiler refers to the amount of energy it uses to perform its everyday functions as well as the amount of energy it wastes.

The Worcester Bosch Greenstar Heatslave II 18/25 has been given a rating of 90% for energy efficiency, equivalent to a SEDBUK "A" rating.

In 2015, new legislation was introduced by the EU to encourage manufacturers to develop more energy-efficient products that emit fewer harmful gases throughout their lifetime.

The Energy Related Products Directive (ERP) applies to all products that consume energy, including during the manufacturing process, at the point of final disposal, and all points in between.

The ERP rating of the Worcester Bosch Greenstar Heatslave II 18/25 is "A" for heat and "B" for hot water.

How long is the warranty offered by the manufacturer for the Worcester Bosch Greenstar Heatslave II 18/25 boiler?

The Worcester Bosch Greenstar Heatslave II 18/25 is covered by a parts and labour warranty of 2 years following installation.


The top 10 rated Oil Combi boilers

Using the Plumbproud scoring system, the current 10 ten Oil Combi boilers assessed using a number of important variables are as follows:

1Worcester Bosch Greenstar Heatslave II 12/1876.19%
2Worcester Bosch Greenstar Heatslave II 18/2576.12%
3Worcester Bosch Greenstar Heatslave II External 12/1875.95%
4Worcester Bosch Greenstar Heatslave II 25/3275.83%
5Worcester Bosch Greenstar Heatslave II External 25/3275.58%
6Grant Vortex Pro 2167.46%
7Grant Vortex Pro 2667.43%
8Grant Vortex Pro 26kW67.35%
9Grant Vortex Pro 2167.31%
10Grant Vortex Pro 2667.14%
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