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Worcester Bosch Greenstar 4000 Boiler Review & Price Guide

Worcester Bosch Greenstar 4000 review – Is the new range any good?

worcester bosch greenstar 4000 review

This Worcester Bosch Greenstar 4000 review will tell you everything you need to know about the UK’s most popular gas boiler for central heating, which is available now in a range of outputs if you are looking to replace your old boiler.

In just 20 seconds, you can get a fixed price here for a Worcester Bosch Greenstar 4000 – Get your quote now!

The Worcester Greenstar 4000 has a 10-year warranty (or 12-year warranty if purchased from Boiler Central, our recommended installers) and has won numerous Which? Best Buy awards. It has a fresh new look, an intuitive full-colour text display, and is also remarkably quiet.

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Worcester Bosch Greenstar 4000 boiler review

The Worcester Bosch 4000 is a series of gas-fired boilers created by Worcester Bosch, a prominent name in the heating sector. The range consists of combi and system boilers designed to deliver dependable and efficient heating and hot water for households of small to medium size.

The combi boilers in the Worcester Bosch 4000 series are designed to offer instant hot water and central heating, without the need for a separate hot water tank, making them ideal for small homes with limited space.

The system boilers, on the other hand, require a separate hot water cylinder to store hot water, thus making them better suited for larger homes or those with higher hot water demands.

The Worcester Bosch 4000 series integrates several energy-saving functions, such as a high-efficiency pump, a low-energy mode, and a modulating heat output, which adjusts to the heating system’s requirements.

Worcester Bosch 4000 logo

The Worcester Bosch 30i combi boiler has been replaced by the Worcester 4000 combi boiler, and the system boiler range has replaced the Greenstar I system boiler range. Check to see if these make our list of what the best combi boiler is.

Part of the new Worcester Bosch Greenstar boiler range

When it comes to any Worcester Bosch combi boiler, the quality is always amazing and the products they offer are mostly second to none.

This new boiler range is aimed at the mid-range of the Worcester line, with the 2000 series serving as the entry-level model and the 8000 series serving as the range-topping, full-service model.

This Greenstar 4000 combi boiler range, like the old Greenstar I range, is available in 25kW and 30kW versions. The cost of a new boiler installation is slightly higher, but this is most likely due to the fact that it is a completely new range.

The best part about switching to one of these new A-rated combi boilers is that you can lower energy bills and save up to £800 per year.

Did you know that Boiler Central offers a market-leading 12-year warranty?

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Top Features of the Worcester Bosch 4000 combi boiler

worcester bosch greenstar 4000 review
  • Really long warranties (10 years standard, 12 years with mavericks Boiler Central)
  • Perfect for small and medium-sized homes
  • Available in 25kW or 30kW for flexibility
  • Priced competitively around £1,940 for a combi swap
  • ErP rating 94%: A-rated
  • Dimensions H 710mm x W 400mm x D 310mm
  • Can be used with smart thermostats/phones
  • Super reliable & trusty all-year-round
  • The cutting-edge new design has an appealing colour display
  • Operates extremely great whilst working with low water pressure areas, providing powerful and warm showers.
  • Wide power range aids in lowering energy costs and gas usage
  • Innovative “Quick Tap” water-saving technology aids to reduce water waste.
  • Ensures strong and warm showers even in places with low water pressure.
  • Features wireless connectivity alongside Bosch’s EasyControl thermostat.
  • Instantaneous hot water is always available thanks to one of the quietest combi boilers available.
  • The quieter operation allows for less annoying noises.

The Worcester Greenstar 4000 can run on a 20% Hydrogen Blend

You’ll be able to unwind knowing that there’s no need to modify your heating systems because the government has promised to make this happen by 2025.

Worcester 4000 combi boiler models

As briefly mentioned above the wide power range available for the Greenstar 4000 comes in two different power outputs and heat output for combi boilers: Combi boilers are the most popular type of boiler in the UK right now.

  • Worcester Bosch Greenstar 4000 25kW
  • Worcester Bosch Greenstar 4000 30kW

We have reviewed each of the boilers below but the best thing about having 20 options in this range means that it makes this Worcester Bosch model suitable for small to medium-sized homes in the UK, making it the right boiler for you.

If you need something more powerful you would have to go for the Worcester Bosch 8000 combi boiler.

Worcester Bosch Greenstar 4000 25kw combi boiler

The 25kW version is perfect for small and medium homes with up to 14 radiators or medium household sizes with one bathroom. Boasting a flow rate of 10.5 litres per minute which is more than enough for most homes.

This is the lower output model, so ensure that you only have one bathroom and low water demands if you choose this option.

Worcester Bosch Greenstar 4000 30kw combi boiler

The 30kW version is probably more suited for those with a little higher demand, with 16, maybe 17 radiators to give you a guide on the extra capabilities.

The 30kW 4000 really would be worthwhile if you have multiple showers or baths in use sometimes as it has a higher flow rate of 12.3 litres per minute to cope with a little more than the 25kW version.

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Worcester Bosch 4000 dimensions

The Worcester 4000 dimensions are so important if you are thinking of putting it somewhere that is a tight space such as a kitchen cupboard. During the installation, this combi is so great that it can be installed in a kitchen cupboard, but it isn’t the most compact so we always suggest that you measure up first.

710mm (height)400mm (width)310mm (depth)

Out of all the mid-rage boilers, even though it is still compact, it is one of the larger boilers. If you want something more compact we suggest the Ideal Logic C30 combi boiler.

Worcester Bosch Greenstar 4000 system boiler

The Worcester 4000 system boilers are just as good as the combi. Although boilers that are system models are gradually declining in popularity due to combi boilers being able to power higher flow rates every year, there is still a decent demand for system boiler replacement quotes in the UK.

What is a system boiler?

A system boiler is where you have a boiler and also a separate water tank, usually in the airing cupboard. Simple. We have a system boiler price guide if you need help choosing your boiler upgrade.

What sizes are the 4000 system boilers available in?

The system gas boiler range of this new Greenstar 4000 is below:

  • Worcester 4000 12kW System
  • Worcester 4000 15kW System
  • Worcester 4000 21kW System
  • Worcester 4000 24kW System

How do you know which of the Worcester Greenstar system boilers is suitable for your home? The easiest way is to use our free online calculator here.

How energy efficient is the boiler?

The Worcester Bosch Greenstar 4000 received an A rating for energy efficiency (at an amazing 94%). With 25kW and 30kW combi boiler options, as well as a variety of system options for larger houses, it serves a wider clientele.

Worcester Bosch’s latest model has all of the latest additions to make it as efficient as possible so your heating bills can be the lowest they’ve ever been.

Unless you’re heavy on the thermostat. Whilst on thermostats, you can link these to a nest or hive to get extra efficiency savings.

Worcester Bosch controls

Frost protection

Most Worcester Bosch boilers have frost protection and the 4000 range is no different. A really nice addition to this boiler for peace of mind.


Exactly what it says – eco mode will save you money on your energy bills and heating bills as well as reduce gas consumption by emitting less carbon into the environment. Great news all around!

A new look and a modern new design

This superb mid-range 4000 boiler has a new look which has a modern new design and really user-friendly too. It features a lovely sleek design in a compact size so if you can’t fit it in your kitchen cupboards, it’ll look fine on display.

Are the display and controls any good?

The display is a nice, easy-access push-button control on a black circle at the base of the boiler. It features wireless connectivity so you can connect a Worcester Bosch EasyControl and power it remotely from your phone or tablet for example.

Side panels are easy to access for engineers

When you get your boiler serviced (you should annually to keep your warranty valid) the Gas Safe engineer will need to get ‘into’ your boiler.

Worcester has made it really easy with removable side panels access which means they can access what they need quickly and easily.

Intelligent filling system (combi only)

As with the old Greenstar i that this model has been upgraded from, the 4000 range has the same intelligent filling system fitted to help keep your central heating water pressure at the right level.

The Worcester intelligent filling system is compatible with the Greenstar 4000 line. This technology makes use of software that can keep the pressure in your boiler at its ideal level. The internal filling valve will automatically replenish the system if the pressure drops, then turn off when it has finished. Additionally, it will notify you if the boiler is losing excessive pressure, saving you from needless engineer callouts.

Therefore, if the pressure is lower than it should be, the internal filling valve will open, filling the heating system to the proper level automatically, and then turning off again. A leak in the heating system, for example, may cause the pressure to drop too low, which would signal a problem.

This feature is exclusive to the combi and is not accessible with the 4000 system boiler.

Greenstar 4000 control compatibility Review

The Greenstar 4000 range is compatible with Worcester Bosch’s other boiler controls such as:

  • Worcester Bosch EasyControl
  • Comfort+ RF
  • Comfort+ Stats RF
  • Comfort +
  • MT20

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Boiler warranty

The standard warranty on the Worcester 4000 is 8 years out of the box from Worcester, and if you want to get the full 10-year warranty from them, you have to upgrade the system filter to a better WB system filter, which as you can imagine will affect the cost.

When purchased from Boiler Central, the Greenstar 4000 comes with a 12-year warranty regardless at no extra cost. Get a fixed online price by clicking get a quote.

However, no one else can offer you (included in the price) this exclusive extended warranty period if you go with anyone else. Terms and conditions apply, but please check with them first.

Other companies are lacking in you know the “warranty department,” so most providers will provide a 7 to 10-year warranty.

You should choose the longest warranty possible so that if you decide to sell your home, having a worry-free boiler warranty will add value and protect you if you have any Worcester boiler problems.

How much does the Worcester Bosch 4000 cost?

Anyway, just in case you took the slow option, here is how much the Worcester 4000 costs:

For the 25kW and 30kW combi boiler Greenstar 4000 prices, you can expect to pay around £1,950 to £2,095 with a horizontal flue, or add £200 for a vertical flue. These costs don’t include moving the boiler etc, literally just the price of a Worcester 4000 boiler swap.

If you use one of our recommended boiler installation companies such as Boiler Central, you can even get this boiler on finance and pay monthly to spread the cost. You don’t have to finance it all, you can put a deposit down. There are also interest-free finance options available too.

If you want to pay less for your boiler but still want a Worcester, why not consider the Worcester 2000 combi boiler that is at the budget end of the market?

Worcester Bosch 4000 prices with installation

Here are the latest Worcester Bosch 4000 prices, but if you want to see the full range, view the latest Worcester Bosch boiler prices here.

Worcester Bosch Greenstar 4000 25kW combi boiler£2,035
Worcester Bosch Greenstar 4000 30kW combi boiler£2,095

If you want to move your boiler’s location you can add £400 to £600 depending on where it’s going and if your converting from a system boiler (with tank) to a combi then add another £600(ish) to the cost.

Again you can use our free online calculator here to give you accurate pricing.

Why you should buy the Worcester Bosch 4000?

Is the Worcester Bosch 4000 the right boiler for me? Well, this all falls into house size, availability and power outputs available and if a new boiler is suitable for you.

In our article discussing, the best boiler brands and the best boiler manufacturers, we put Worcester Bosch at the top. As well as the Greenstar 4000 as the top Worcester Bosch combi boiler to date. So having this boiler installed is just as favourable as a nice day out. So if you’re looking for a new boiler installation, look no further. Or if you want to replace your old boiler with a new boiler, that is just as smart.

The most recent of these boiler brand advancements, including the intelligent filling system, frost prevention, ECO mode, and wireless connectivity, are also advantageous to the 4000.

Worcester Bosch 4000 – Our review & conclusion

Simply put, this mid-range boiler from probably the best boiler brand Worcester Bosch is probably going to be the most-sold boiler in the UK over the coming 12 months. It is in direct competition with the superb value Viessmann Vitodens 050-w combi boiler which is already smashing the UK market. If you’re looking for a new boiler, your search ends here!

It has everything. The only thing we think is even better is Boiler Central’s 12-year warranty – these guys are the mavericks of the boiler industry so if you are looking to buy the 4000 boilers, price one up with them here.

Other than that, we hope this review has been helpful in your decision on whether the new Greenstar 4000 is the boiler for you!

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