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Worcester Bosch Greenstar Heatslave II 12/18 boiler

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Plumbproud rating

76.19%

Worcester Bosch Greenstar Heatslave II 12/18 Combi Oil boiler

We scored this Worcester Bosch Greenstar Heatslave II 12/18 Combi boiler at 76.19% on our internal benchmarking system. To determine a score, we take into consideration a number of different factors including the boiler's energy efficiency, installed price, likely running costs, and the length of the manufacturer's warranty.

This Worcester Bosch Greenstar Heatslave II 12/18 Combi boiler will cost around £3,500 fitted through PlumbProud where there are no complications during the installation.

To receive a free quote on the Worcester Bosch Greenstar Heatslave II 12/18 boiler, as well as professional advice on whether it will meet the needs of your home, simply enter your postcode in the quote box on this page, click here to email us, or call 01604 343053.


Installed price around

£3,500

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

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

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

Combi boilers have much to recommend them - not least the fact that they save a lot of space. Combination (or combi) boilers were introduced by manufacturers in the 1970s to provide practical central heating and hot water distribution to smaller properties - remember that UK houses and flats tend to be among the smallest in the developed world.

Traditional boilers require one or more storage tanks to keep hot water warm and to store water for heating later. In contrast, combi boilers draw water directly from the mains supply and heat it instantly, removing the need for a storage tank. The heated water is then distributed to your taps and radiators on demand.

While combi boilers are suitable choices for many properties, especially those without a loft, there is also a disadvantage in using them. Water is heated instantly and the volume of water that can be heated at any one time is limited. This can result in less water being sent to taps and showers if more than one is being used simultaneously. In these instances, the water pressure to both points will drop.

Is the Worcester Bosch Greenstar Heatslave II 12/18 combi boiler the right choice for my house or apartment?

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

The output of a boiler is measured in kilowatts and indicates how much energy it can use to heat the water needed for your radiators, taps and showers. The greater the output, the more water it can heat.

A boiler whose output is too high will give you hot water and warm radiators but also higher oil bills, whereas a boiler whose output is too low will result in cheaper oil bills but the water might not always be as hot as you want it to be.

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

An experienced boiler engineer would recommend that this Worcester Bosch Greenstar Heatslave II 12/18 Combi boiler would be a suitable installation choice for smaller homes and apartments with up to 10 radiators and one bathroom.

You should also consider a combi boiler's "flow rate" when making your choice.

The flow rate indicates how much water it can take from the mains supply at any one time (measured in litres per minute), which it then heats and distributes to different points in your home like your bathroom, kitchen and radiators. This Worcester Bosch Greenstar Heatslave II 12/18 Combi boiler's flow rate is 15 L/m.

Combi boilers have no storage tanks like system or heat only boilers. This means that if the water pressure where you live is low, there's no benefit in spending money on a combi with a high flow rate because a high flow rate doesn't mean it can draw any more water from the mains.

In addition, there might be lots of people in your household who want to use hot water at the same time while also having the central heating on. Given that average mains pressure in the UK is between 10 and 12 litres per second and a power shower usually requires about 12 litres of water per minute, a combi boiler might not be the right choice for you and your family.

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 big is the Worcester Bosch Greenstar Heatslave II 12/18?

The Worcester Bosch Greenstar Heatslave II 12/18 measures 855 mm in height by 520 mm in width by 600 mm in depth.

Many homeowners dislike the floor-standing boilers (like the Worcester Bosch Greenstar Heatslave II 12/18) they have in their properties because they feel that they are bulky and take up too much room. If this is you and you want to replace what you have now with a compact, wall-mounted boiler, we can do this for you, although please note that you may need to pay for new piping.

The oil bill savings offered by modern boilers are significant, however, and you should be able to recoup your investment in a few years.

If you are going to replace your current heat only or system boiler with the Worcester Bosch Greenstar Heatslave II 12/18, you'll also need to budget for the removal of your hot water cylinder and/or expansion tank.

Please get in touch with PlumbProud if you would like information and guidance on the best course of action and we will share our advice with you.

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

We recommend that you choose a condensing boiler wherever possible like the Worcester Bosch Greenstar Heatslave II 12/18 - try to go for the latest model, if possible, to take advantage of improving technology.

Condensing boilers capture and recycle the warmth still present in the water vapour condensation and in flue exhaust emissions created by burning oil to make them more efficient and economical to run.

You will save money on your oil bills too, plus condensing boilers are friendlier to the environment.

Does the Worcester Bosch Greenstar Heatslave II 12/18 combi protect the environment?

How we heat our homes is an issue which many homeowners worry about as the world combats climate change and environmental damage.

The heating of our homes accounts for 14% of the UK's greenhouse gas emissions. Especially in the big cities, gas boilers are responsible for dangerous levels of nitrogen dioxide emissions.

Will installing a Worcester Bosch Greenstar Heatslave II 12/18 combi in your home be a positive contribution to the environment? The figures below will tell you more.

All boilers manufactured and supplied in the UK must achieve an energy efficiency rating of at least 92% (an "A" SEDBUK grade). This is higher than the previous 88%, which was a legal requirement prior to April 2018.

The energy efficiency rating is used to work out how much energy a boiler both uses and wastes when it's switched on and working correctly - its standard functioning and operation.

The Worcester Bosch Greenstar Heatslave II 12/18 is rated as 90% energy efficient, equivalent to a "A" SEDBUK 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 12/18 has an ERP rating of "A" for heat and "B" for hot water production.

How long is the warranty offered by the manufacturer for the Worcester Bosch Greenstar Heatslave II 12/18 boiler?

The Worcester Bosch Greenstar Heatslave II 12/18 is supplied with a parts and labour warranty of 2 years.


Worcester Bosch Greenstar Heatslave II 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
Height855 mm
Width520 mm
Depth600 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%

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Worcester Bosch Greenstar Heatslave II 12/18 boiler

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Worcester Bosch Greenstar Heatslave II 12/18 Combi Oil boiler

  1. Home
  2. Worcester Bosch Greenstar Heatslave II 12/18
Plumbproud rating for this boiler
76.19%

We have determined a rating of 76.19% for this Worcester Bosch Greenstar Heatslave II 12/18 Combi boiler on the PlumbProud quality scoring system. The rating is determined using a variety of important factors including price installed, manufacturer guarantees, energy efficiency and the likely cost of running.

On straightforward installations, we would expect to charge you £3,500 for this Worcester Bosch Greenstar Heatslave II 12/18 Combi boiler fully installed.

Get a free, no-obligation Worcester Bosch Greenstar Heatslave II 12/18 boiler quote today by simply entering your postcode in the box on this page. You can also speak to a boiler installation expert about heating for your home by getting in touch via email or by phone on 01604 343053.


Installed price guideline
£3,500

Get your free quote

Worcester Bosch Greenstar Heatslave II 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
Height855 mm
Width520 mm
Depth600 mm
MountingFloor
Flow rate15 L/m
ERP HeatA
ERP WaterB

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

Is the Worcester Bosch Greenstar Heatslave II 12/18 boiler a standard, combi or system model?

The Worcester Bosch Greenstar Heatslave II 12/18 boiler could be suitable for your house or flat if you are looking for a new combi boiler.

Combi boilers are excellent for providing hot water and heat for your radiators just when you need it. When you have a combi boiler installed in your home, you just turn on the tap and the hot water for your bath, shower, washing dishes and other activities is there when you need it. It also provides the heat you need to keep your radiators warm.

A combi boiler heats the cold water passing through it, which it draws from the mains. This newly heated water can then be distributed to whichever hot tap or radiator needs it.

In the past, boilers needed at least one storage tank to hold water that was either already heated or would be heated later. Sometimes, you'd have to wait for hot water because there was none left. In addition, storage tanks took up a lot of space and most UK homes are pretty small.

The main disadvantage to combi boilers is that they can only heat a certain amount of water at any one time, meaning the pressure, volume and temperature of water will decrease if more than one tap is on at the same time or if both the shower and washing machine are on together.

Is the Worcester Bosch Greenstar Heatslave II 12/18 combi suitable for my house or flat?

To determine that, we need to consider the size of the boiler. Size doesn't mean how big it is - it means how big its "output" is.

Your boiler's output indicates the maximum amount of power available to it to heat the water you need to warm your radiators or when you want hot water from your taps. A higher output rate means that your boiler is capable of heating greater volumes of water.

If a boiler's output rate is too low, you'll often find that the water is not as hot as you want it to be. Too high, however, and you'll end up paying more for your oil than you should be.

The Worcester Bosch Greenstar Heatslave II 12/18 combi boiler has an output rate of 18 kW, so which types of property would this be suitable for?

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

As well as the output rate, you need to consider "flow rate" when choosing a combi boiler.

The flow rate describes how much water a combi boiler can draw from the mains, instantly heat, and then send to your radiators. Flow rates are measured in litres per second and this Worcester Bosch Greenstar Heatslave II 12/18 Combi boiler's flow rate is 15 L/m.

The water in your mains pipe also has its own flow rate - normally between 10 and 12l/m in most parts of Britain. This means that, if you choose a combi boiler with a flow rate of 17l/m where local water pressure is 11lm, it won't actually process more water because of the slower flow rate of the mains.

In addition, larger households with more than one bathroom, multiple radiators, and where family members may want to use hot water at the same time (like morning showers) may actually need a boiler with a higher flow rate than either the boiler or the local mains pipe.

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 12/18 boiler?

The Worcester Bosch Greenstar Heatslave II 12/18 is 855 mm [H] by 520 mm [W] by 600 mm [D] in size.

If you use a floor-standing boiler like the Worcester Bosch Greenstar Heatslave II 12/18 for your central heating and you're interested in replacing it with a more compact, wall-mounted boiler, you can. Wall-mounted boilers have been the most popular choice over the last two decades among homeowners wanting to create more space within their properties. Bear in mind that, while wall-mounted units are cheap, you may have to pay more for installation if your current piping needs replacing because it's not compatible with your new system.

This additional cost would however be recouped in full over a few years because of the savings you make on your quarterly oil bills.

If you are considering the Worcester Bosch Greenstar Heatslave II 12/18 as a replacement for your existing heat only or system boiler, you'll also have to budget for the removal of your hot water cylinder and/or your expansion tank.

If you would like professional information and guidance on the best choices for your home, please contact PlumbProud for advice.

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

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

With a condensing boiler, you save money on your oil bills because your boiler captures and recycles the heat present in the flue exhaust gases and water vapour condensation for re-use, meaning they operate far more economically and efficiently.

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

How we heat our homes and the effect that has on climate change has become important to many homeowners worried about the environment.

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 installing a Worcester Bosch Greenstar Heatslave II 12/18 combi in your home be a positive contribution to the environment? The figures below will tell you more.

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 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 ERP, short for the Energy Related Products Directive, is a European directive aimed at encouraging manufacturers to create products that are environmentally friendlier at all stages, including during manufacturing, when the product is in active use, right through to the point of final disposal.

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

Is this Worcester Bosch Greenstar Heatslave II 12/18 combi covered by a warranty?

On the Worcester Bosch Greenstar Heatslave II 12/18, the manufacturer offers a parts and labour warranty of 2 years.


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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