Worcester Bosch Greenstar 8000+ Combi Boiler Cost with Installation

The Greenstar 8000+ is Worcester Bosch’s most powerful combi boiler, built for large, busy homes with high hot water demand. 

It features a full-colour touchscreen, an intelligent self-filling system, a Quiet Mark certification, and an 8-year standard guarantee extendable to 12.

So, let’s have a closer look at some of the Worcester Bosch Greenstar 8000+ combi’s specs:

Worcester Bosch Greenstar 8000+ Combi Product Table
	Available outputs	32kW	36kW	40kW	45kW	50kW
	Type	Combi
	Fuel	Gas
	Condensing	Yes
	Efficiency rating (%)	94
	ErP	A
	LPG compatible	Yes
	Standard guarantee	8 years*
	Max output (kW)	32	36	40	45	50
	Flow rate (l/min)	12	13.5	15	16	16
	Mounting	Wall-mounted
	Dimensions (mm)	780 x 440 x 365
	Typical price (incl. VAT)	£1,650	£1,750	£1,850	£1,950	£2,100
	Typical installation cost (incl. VAT)	£800 – £1,400
	Total cost	£2,450 – £3,500

*Terms and conditions apply.

Worcester Bosch Greenstar 8000+ combi overview

The Greenstar 8000+ is Worcester Bosch’s flagship combi boiler, designed for large homes where heating and hot water demands are high. 

With five output sizes spanning 32kW to 50kW, it covers more ground than most combi rivals, and its hot water flow rates, up to 16 litres per minute, mean it can handle two bathrooms running simultaneously.

As a combi, it delivers heating and hot water directly from the mains with no cylinder or loft tank required. The intelligent filling system automatically monitors and tops up system pressure, removing the need for most homeowners to ever locate or use a manual filling loop. 

Worcester Bosch Greenstar 8000+ Combi Range
Model output size	House size	Bathrooms	Radiators
32kW	Medium homes, 3 to 4 bedrooms	1-2	Up to 15
36kW	Medium-large homes, 4 to 5 bedrooms	2	Up to 15
40kW	Large homes, 4 to 5 bedrooms	2-3	Up to 20
45kW	Large homes, 5+ bedrooms	2-3	Up to 20
50kW	Very large homes, 5+ bedrooms	3+	20+

Key benefits at a glance

• ErP A-rated efficiency (94%)
• Full-colour touchscreen display
• Intelligent Filling System which maintains pressure automatically
• RF Key receiver for wireless smart thermostat pairing (thermostat sold separately)
• Five output sizes (32-50kW)
• Quiet Mark certified
• Digital pressure gauge, readable when the boiler is off
• Front-access PRV, removable in under 10 minutes
• LPG variants available across the range
• 8-year standard guarantee, extendable to 12 years*

Worcester Bosch Greenstar 8000+ combi technical specifications

This is a combi for the bigger houses, so in a likely already noisy house you’ll appreciate the Quiet Mark certification. The 8000+ is engineered to run quietly enough for installation close to living spaces without causing disruption.

Output and efficiency ratings

All five output sizes achieve 94% efficiency and an ErP A-rating for both heating and hot water, meaning less wasted fuel. You’ll be grateful for this when the energy bill comes through!

Hot water flow rates increase from 12 l/min at 32kW to 16 l/min at 45kW and 50kW, with the most useful step-up occurring between 36kW (13.5 l/min) and 40kW (15 l/min) for homes with two bathrooms in simultaneous use.

Dimensions 

All models share the same footprint: 780mm high, 440mm wide, 365mm deep. At 780mm tall, it won’t fit inside a standard kitchen cupboard, so most installations are in utility rooms or directly on a wall (though Worcester Bosch have designed it to be displayed rather than hidden, with a clean modern finish that suits an open installation).

Components included

The Intelligent Filling System is the feature most homeowners appreciate after they’ve lived with it. Boiler pressure drops for all sorts of reasons and on most boilers that means locating the filling loop (often behind a panel or in an awkward cupboard), working out which way to turn it, and hoping you don’t overshoot. The 8000+ monitors pressure continuously and tops itself up automatically. Worcester Bosch are also clever about it: if pressure drops repeatedly or suddenly, the system recognises that’s not normal and stops filling rather than masking a leak. You get an alert on the display instead.

A small detail, but a useful one is that digital pressure gauge on the 8000+ remains readable without power. This matters if you’re checking on the boiler after a trip away or during a power cut. On most boilers, the display goes dark the moment there’s no power.

Most boiler displays show a fault code (e.g. E9, F4) that means nothing to anyone without a manual or a quick Google. The 8000+ displays the fault in plain text, this makes a world of difference for a homeowner trying to work out whether to call an engineer or just reset it. It also means when you do call someone out, you can tell them exactly what the display says.

The RF Key receiver built into the boiler lets a compatible smart thermostat pair wirelessly, so there’s no need to run cables from the thermostat back to the boiler. This is particularly relevant in older properties where running cables through walls is disruptive and expensive. The thermostat itself, Worcester Bosch’s EasyControl, is a separate purchase, but the receiver is ready and waiting for a quick set up.

Prices and installation costs

Let’s take a look at what a Worcester Bosch Greenstar 8000+ combi will typically cost you. The standard price covers the boiler unit and a horizontal flue. A horizontal side-wall flue costs roughly £100-£150; a vertical roof flue can exceed £500. 

LPG variants are available as separate factory-built units across the full output range. 

If smart app control is a priority, budget an additional £100-£200 for the Bosch EasyControl thermostat.

Worcester Bosch Greenstar 8000+ Combi Costs
Output size	Unit cost (incl. flue)	Total (incl. installation)
32kW	£1,650	£2,850
36kW	£1,750	£2,950
40kW	£1,850	£3,050
45kW	£1,950	£3,150
50kW	£2,100	£3,300

Warranty and support

The 8000+ comes with an 8-year standard warranty, which beats both Vaillant and Viessmann with their 5-7-year warranties. This rises to 10 years when a Greenstar System Filter is fitted, and to 12 years for Worcester Bosch loyalty scheme members who are not accredited installers and pay an additional £40 via their loyalty account. Worcester Bosch Accredited Installers (WAI) can achieve the 12-year guarantee with a filter and their WAI status.

Annual servicing with a completed Benchmark checklist is required to keep the guarantee active. It’s worth noting that Worcester Bosch offers a guarantee rather than a standard warranty, meaning they commit to repairing the boiler regardless of cause, not just manufacturing faults, for the duration of the cover period.

💡 WhatPrice Insight: Even at its baseline of 8 years, the 8000+ guarantee tops the standard offering from most rivals. To maximise your cover from day one, confirm at the quoting stage that your installer will fit a compatible system filter and submit the guarantee registration promptly. 

Installation information

A standard installation typically costs around £1,200. A direct like-for-like swap will sit at the lower end but with boiler relocation, pipework upgrades, or a complex flue, costs will be pushed higher.

What to expect on installation day

If additional work is required – such as upgrading pipework or relocating the boiler – your installer should explain this clearly beforehand, including any impact on cost or installation time.

Do you need a system flush or filter?

Yes, a magnetic filter is mandatory under UK Building Regulations, and fitting one also directly improves the warranty you qualify for. 

A powerflush is not legally required but is strongly recommended to clear any sludge from existing pipework before it can circulate through the new heat exchanger. 

Expect to pay £350-£800 for a system flush and £65-£300 for a magnetic filter.

Finding a Gas Safe registered engineer

All installations must be carried out by a Gas Safe registered engineer by law. Choosing a Worcester Bosch Accredited Installer also helps maximise your warranty length. 

Reviews and ratings

Worcester Bosch is one of the most highly rated boiler brands with a 4.6 out of 5 stars on Trustpilot. 

We’ve collated reviews specifically relating to the Worcester Bosch Greenstar 8000+ combi, which you can see below: 

Positive reviews

Quiet operation comes up repeatedly with reviewers consistently noting how much quieter the 8000 series is compared to their previous boiler, one homeowner described having to check whether it was still running at all!

Several customers also report noticeable reductions in energy bills within the first year, particularly those upgrading from older boilers.

The automatic pressure system draws specific praise from homeowners who previously had to top up their boiler manually. One reviewer noted they’d had their boiler in a loft for years and regularly had to climb up to reset the pressure, with the 8000+ they described the automatic refill as a genuine relief. Another simply said it “hardly needs topping up with water” after a year of use.

Customers upgrading from older Worcester Bosch models comment that the digital display is easy to navigate, and several mention the boiler pairing with their existing Nest or Hive thermostat without any issues. 

Negative reviews

Hot water delivery speed is the most complaint in the reviews. One homeowner found the 8000+ couldn’t keep up with a bath tap at full flow, with the water going tepid before the bath filled. Worcester Bosch’s response suggested reducing the flow rate, which the reviewer felt defeated the point. 

💡TopTip: This is why it’s so important to make sure the output model is matched to your home’s hot water demands. An undersized boiler can struggle to keep up, whilst an oversized boiler can run less efficiently and cost you more in the long run.

A separate reviewer noted their hot water takes around 40 seconds to reach the kitchen tap, and says they miss the near-instant response of their previous boiler.

Two customers report rattling or vibration during operation, one of whom described it as needing “a gentle tap” to stop. 

One reviewer reported repeated breakdowns with fault codes through winter, requiring three separate engineer visits before the problem was resolved with each replacing a different part. 

How the Worcester Bosch Greenstar 8000+ combi compares

Worcester Bosch Greenstar 8000+ Combi Comparison Table
Model	Vaillant ecoTec Exclusive combi	Worcester Bosch Greenstar 8000+ combi	Viessmann Vitodens 100-W combi
Typical unit price	£2,000	£1,950	£1,400
Heat exchanger	Stainless steel	Aluminium	Stainless steel
Standard warranty	5 years	8 Years	5-7 years
Max warranty	10 years	12 Years	10-12 years
Built-in WiFi	No (optional via myVAILLANT connect gateway)	No (RF Key for optional thermostat)	Yes
App control	myVAILLANT/vSMART	Bosch EasyControl	ViCare
Cupboard fit	Yes	Yes	Yes
Max output/bathrooms	43kW 2-3 bathrooms	50kW 3+ bathrooms	35kW 2 bathrooms

Final thoughts – is the Worcester Bosch Greenstar 8000+ combi right for you?

The boiler most worth comparing this against is the Vaillant ecoTEC Exclusive Green iQ, and the comparison is closer than you’d think. The Vaillant has a stainless steel heat exchanger where the 8000+ uses aluminium, this a difference that starts to matter after year ten, particularly if you’re in a hard water area. The Vaillant also fits in a cupboard; at 780mm the 8000+ doesn’t, and that’s not a small thing if your kitchen layout depends on it.

Where the Worcester pulls back ahead is the guarantee. Twelve years of cover that explicitly includes repair regardless of cause sets the Greenstar 8000+ apart from any other combi in its price bracket. 

The other thing the Vaillant can’t touch is the output range. The ecoTEC Exclusive only goes up to 43kW. If your home needs more than that, this isn’t a like-for-like comparison as the 8000+ is your only premium combi option.

The Intelligent Filling System handling pressure automatically is a bonus that becomes useful in everyday life, particularly if the boiler is installed somewhere out of the way.

If you have a large home but the 8000+’s heat exchanger material is a real concern, the Vaillant ecoTEC Exclusive is where to look, not the Viessmann Vitodens, which won’t cover a big house at 35kW. But for most people buying at this end of the market, the Worcester’s combination of longer cover and higher output is what justifies the price.

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