GET A COMPETITIVE QUOTE

Please enter your postcode below to get a free, no obligation, personalised quotation from PlumbProud

Worcester Bosch Greenstar Heatslave II External 12/18 boiler

  1. Home
  2. Worcester Bosch Greenstar Heatslave II External 12/18
Plumbproud rating

75.95%

Worcester Bosch Greenstar Heatslave II External 12/18 Combi Oil boiler

This Worcester Bosch Greenstar Heatslave II External 12/18 Combi boiler scores 75.95% on our PlumbProud boiler quality benchmark tests. To determine our rating, we consider many factors, such as the cost of installation, manufacturer guarantees, energy efficiency, and likely running costs.

This Worcester Bosch Greenstar Heatslave II External 12/18 Combi boiler is likely to cost around £3,700 fully installed by PlumbProud if there are no unexpected complications during the fit.

Get a free quote on the Worcester Bosch Greenstar Heatslave II External 12/18 boiler and advice on whether this is the right choice for your home by entering your postcode in the quote box on this page, clicking here to email us, or giving us a call at 01604 343053.


Installed price around

£3,700

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 External 12/18 Combi Oil boiler frequently asked questions

Which category of boiler does the Worcester Bosch Greenstar Heatslave II External 12/18 fit into?

You might want to consider the Worcester Bosch Greenstar Heatslave II External 12/18 for your house or flat if you are looking for a combi boiler.

Boilers traditionally required the installation of one or more large tanks around your property. These were filled with water that was either being heated or was to be heated later. British homes are among the smallest in the world so, to solve the space problem, manufacturers introduced combi boilers in the 1970s to offer homeowners the warmth and hot water supply they needed while taking up much less space.

A combi boiler is designed to heat both radiators and taps on demand and at the same time. Water from the mains passes through a combi boiler and the boiler's technology instantly turns it into hot water. Your boiler then distributes the hot water throughout your home.

The main disadvantage of combi boilers is that they have a maximum water volume capacity. What this means is that, if one person is using the shower while another uses a hot tap simultaneously, less water gets to each area, resulting in a fall in water pressure at both points.

Is the Worcester Bosch Greenstar Heatslave II External 12/18 combi boiler a suitable choice for my property?

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

The output rate tells you how much energy your boiler has to use to provide you and your family with hot water and central heating. A higher output rate means that it can heat greater volumes of water.

Please be aware, though - if you choose a boiler whose output is too low, the water in your radiators and coming from your taps may not be warm enough. Conversely, if you choose a boiler with too high an output, you'll pay more for oil than is necessary.

The Worcester Bosch Greenstar Heatslave II External 12/18 combi boiler has an output level of 18 kW, so which types of property would it be appropriate for?

Most heating engineers would suggest that the Worcester Bosch Greenstar Heatslave II External 12/18 combi boiler would be a suitable choice for installation in smaller homes and apartments with up to 10 radiators and one bathroom.

Please remember too that all combi boilers draw water from the mains - they have no storage tanks. Combis heat the water from the mains on demand and then send it to wherever it's needed in the house, like a radiator, a bathroom or a kitchen.

The speed at which it can do this is called the "flow rate", which is measured in litres per minute. If you have a lot of radiators and bathrooms in your home and multiple people are regularly trying to use the hot water at one time, such as in the morning or evening, you'll need a combi with a high flow rate. This Worcester Bosch Greenstar Heatslave II External 12/18 Combi boiler's flow rate is 15 L/m.

However, it's not that simple. Combis can only draw water from the mains at the speed it's delivered. If the flow rate of the local water supply is 11l/m, you shouldn't purchase a boiler with a flow rate of 17l/m because it will never be able to use that extra capacity.

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.


The size of the Worcester Bosch Greenstar Heatslave II External 12/18

The Worcester Bosch Greenstar Heatslave II External 12/18 measures 950 mm in height and has a width of 640 mm and a depth of 770 mm.

Floor-standing external combi boilers like the Worcester Bosch Greenstar Heatslave II External 12/18 are housed in a strong weatherproof casing that protects them from rust and water ingress - they also offer much easier access for heating engineers if there is a fault or a repair is needed.

The risk of internal oil leaks and the damage and unpleasant odours they cause is also removed, as is the threat to your family's safety in the event of a carbon monoxide escape (the gas will simply disperse harmlessly into the atmosphere).

Is the Worcester Bosch Greenstar Heatslave II External 12/18 condensing or non-condensing?

The Worcester Bosch Greenstar Heatslave II External 12/18 boiler is a condensing oil boiler and we recommend that you select one of the latest models if possible.

Condensing boilers reduce homeowners' oil bills and are better for the environment. They do this by capturing and recycling the heat still present in the flue exhaust gases and water vapour condensation produced when boilers burn oil to generate the power they need to operate.

Is the Worcester Bosch Greenstar Heatslave II External 12/18 combi rated as environmentally friendly?

How we heat our homes and the damage we might be doing to the environment as a result has become an important point of concern to many homeowners worried about climate change.

With central heating being responsible for 14% of greenhouse gas emissions in the UK, your choice of boiler matters. Gas boilers are also responsible for the significant atmospheric volumes of dangerous nitrogen dioxide emissions in larger British cities.

Would installing a Worcester Bosch Greenstar Heatslave II External 12/18 combi boiler in your home help combat climate change? What do the figures suggest?

By law, boilers manufactured and supplied in the UK must achieve a SEDBUK rating of "A" and work at a 92% minimum efficiency. Before April 2018, a minimum of 88% energy efficiency needed to be achieved (88/89% = SEDBUK "B" and 90% = SEDBUK "A").

Following official testing, the Worcester Bosch Greenstar Heatslave II External 12/18 was given an efficiency rating of 90% with a SEDBUK rating of "A".

Energy efficiency is a measure of how much energy is used and how much is wasted when a boiler is operating.

The Energy Related Products Directive, also known as ERP, is European legislation that intends to reduce energy consumption related to products right from the initial manufacturing process through to eventual final disposal.

The purpose of the directive is to encourage manufacturers to create new products that are kinder to the environment and which result in lower overall harmful gas emissions through a product's entire life cycle.

The Worcester Bosch Greenstar Heatslave II External 12/18 has a rating of "A" for heat and "B" for water.

Is there a warranty on the Worcester Bosch Greenstar Heatslave II External 12/18 combi boiler if it breaks down?

The Worcester Bosch Greenstar Heatslave II External 12/18 boiler has a warranty covering parts and labour costs for up to 2 years after installation.


Worcester Bosch Greenstar Heatslave II External 12/18 Oil Combi boiler specifications

Powered by GasOil
LocationExternal
Condensing?Yes
Efficiency rating90%
Band ratingA
LPG Compatible?No
P/L Warranty2 Years
Output in kW18 kW
Height950 mm
Width640 mm
Depth770 mm
MountingFloor
Flow rate15 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%

Combi boilers

Choose from the UK’s biggest range of combis

Heat only boilers

The ideal boiler perfect for the largest homes

System boilers

Ideal for 3+ bedroom, 2+ bathroom homes

Boiler quote

Free, no obligation quote from our engineer

Worcester Bosch Greenstar Heatslave II External 12/18 boiler

We will not be beaten on price -
ask us about our PRICE GUARANTEE!

Worcester Bosch Greenstar Heatslave II External 12/18 Combi Oil boiler

  1. Home
  2. Worcester Bosch Greenstar Heatslave II External 12/18
Plumbproud rating for this boiler
75.95%

This Worcester Bosch Greenstar Heatslave II External 12/18 Combi boiler has been rated at 75.95%. Our PlumbProud boiler quality rating system uses price installed, energy efficiency, likely running costs, the manufacturer's warranty and other factors to determine the rating we give.

£3,700 is the amount you should budget to have this particular boiler installed on a straightforward installation.

For professional advice on whether the Worcester Bosch Greenstar Heatslave II External 12/18 is the right boiler for your home or to receive a free quotation, please call 01604 343053 to speak to our friendly team. You are also welcome to email us by clicking here or you can enter your postcode into the quotation box on this page.


Installed price guideline
£3,700

Get your free quote

Worcester Bosch Greenstar Heatslave II External 12/18 Oil Combi boiler specifications

Powered by GasOil
LocationExternal
Condensing?Yes
Efficiency rating90%
Band ratingA
LPG Compatible?No
P/L Warranty2 Years
Output in kW18 kW
Height950 mm
Width640 mm
Depth770 mm
MountingFloor
Flow rate15 L/m
ERP HeatA
ERP WaterB

Worcester Bosch Greenstar Heatslave II External 12/18 Combi Oil boiler frequently asked questions

Worcester Bosch Greenstar Heatslave II External 12/18 - a combi boiler, system boiler or regular boiler?

The Worcester Bosch Greenstar Heatslave II External 12/18 boiler is an option you may wish to 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 External 12/18 combi suitable for my house or flat?

Whether this Worcester Bosch Greenstar Heatslave II External 12/18 Combi boiler is right for where you live depends on its size or "output" level. Size does not mean its physical dimensions - it means how powerful it is.

A boiler’s output is a measurement of the amount of power it can use to provide hot water to your taps and radiators. The higher its output rate, the more water it can heat.

If your new boiler’s output is too low, your hot water might not be as hot as you want it to be. If it's too high, you’ll be paying more for oil than you need to.

The output of the Worcester Bosch Greenstar Heatslave II External 12/18 combi boiler is 18 kW, so which types of property would this be appropriate for?

A Gas Safe engineer would recommend that the Worcester Bosch Greenstar Heatslave II External 12/18 combi boiler is a suitable choice for smaller homes and apartments with up to 10 radiators and one bathroom.

If you are thinking about installing a combi boiler like the Worcester Bosch Greenstar Heatslave II External 12/18 in your home, you should consider flow rates as well as output rates. This Worcester Bosch Greenstar Heatslave II External 12/18 Combi boiler's flow rate is 15 L/m.

The flow rate indicates the maximum volume of water (measured in litres per minute) that your boiler can heat up and send to your radiators, taps and showers at any one time. The more taps and showers that could be in use simultaneously or the greater the number of radiators you have, the higher the flow rate you need.

However, you should establish what the mains pressure is at your property as a combi boiler can only heat the water that comes into your home.

For example, if your mains pressure is 12 litres per minute, your boiler can only heat and distribute hot water at a rate of 12 litres per minute even if it has a higher flow rate capacity. Typically, a power shower will require 10 litres of water per minute.

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 External 12/18 boiler?

The Worcester Bosch Greenstar Heatslave II External 12/18 is 950 mm tall, 640 mm wide, and 770 mm deep.

Floor-standing external combi boilers like the Worcester Bosch Greenstar Heatslave II External 12/18 are safer as the oil it uses for fuel is not stored inside your home meaning there is little to no chance of an internal leak occurring which can damage your home and leave oily odours that become difficult to eradicate.

External boilers free up space in your home and because they're outside, you rarely hear them working. In addition, a service engineer can quickly fix it if it has problems, and there is a lower chance of carbon monoxide entering your home.

Is the Worcester Bosch Greenstar Heatslave II External 12/18 non-condensing or condensing?

The Worcester Bosch Greenstar Heatslave II External 12/18 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 choosing the Worcester Bosch Greenstar Heatslave II External 12/18 combi boiler environmentally friendly?

With environmental issues in the spotlight, more and more homeowners are becoming concerned about how they heat their homes and how much they're contributing towards combatting climate change.

Central heating creates 14% of the UK’s greenhouse gases. And in Britain's larger cities, gas boilers are responsible for dangerous levels of nitrogen dioxide emissions.

Will you be helping the environment if you decide to install a Worcester Bosch Greenstar Heatslave II External 12/18 combi in your home? Let’s look at the figures.

By law, boilers manufactured and supplied in the UK must achieve a SEDBUK rating of "A" and work at a 92% minimum efficiency. Before April 2018, a minimum of 88% energy efficiency needed to be achieved (88/89% = SEDBUK "B" and 90% = SEDBUK "A").

Following official testing, the Worcester Bosch Greenstar Heatslave II External 12/18 was given an efficiency rating of 90% with a SEDBUK rating of "A".

Energy efficiency is a measure of how much energy is used and how much is wasted when a boiler is operating.

The Energy Related Products Directive, also known as ERP, is European legislation that intends to reduce energy consumption related to products right from the initial manufacturing process through to eventual final disposal.

The purpose of the directive is to encourage manufacturers to create new products that are kinder to the environment and which result in lower overall harmful gas emissions through a product's entire life cycle.

The Worcester Bosch Greenstar Heatslave II External 12/18 has a rating of "A" for heat and "B" for water.

Will I be covered if the Worcester Bosch Greenstar Heatslave II External 12/18 combi breaks down?

The Worcester Bosch Greenstar Heatslave II External 12/18 boiler comes with a 2 year warranty for parts and labour.


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%
Menu