Key Takeaways
- The Greenstar 1000 is Worcester Bosch’s budget-focused combi boiler, designed primarily for smaller UK homes.
- Both models offer 93% space-heating efficiency and carry an A rating for heating.
- The range comes in 24kW and 30kW versions, with the main difference being their hot-water performance.
- At just 285mm deep, the Greenstar 1000 is compact enough to fit inside many standard kitchen cupboards.
- Boiler size matters. The cheapest or most powerful option isn't automatically right for your home, so consider heating and hot-water demand before choosing.
For many UK households, budgeting has become a fairly permanent part of everyday life.
Even as the worst of the cost-of-living crisis has eased, prices haven’t suddenly rolled backwards. In August 2026, UK Consumer Price Index inflation stood at 3.1%, while the cost of housing and household services was 4.3% higher than a year earlier.
Unfortunately, your boiler doesn’t check your monthly budget before calling it a day.
If your boiler suddenly breaks down, finding a reliable and efficient replacement without spending too much quickly becomes important.
This is where the Worcester Bosch Greenstar 1000 can help.
This model is one of the more affordable options from Worcester Bosch and is made for smaller homes where price, efficiency, and space matter most.
But does picking Worcester Bosch’s budget boiler mean you have to give up important features?
Let’s find out.
What Is The Worcester Bosch Greenstar 1000?
The Greenstar 1000 is Worcester Bosch’s entry-level combi boiler range.
Unlike some boiler families that include combi, system and regular boilers, the Greenstar 1000 is currently available as a combi boiler, with two output options:
- Greenstar 1000 24kW
- Greenstar 1000 30kW
Both models offer up to 24kW of central heating output. The main difference is in hot water performance, as the 30kW model can provide more hot water when needed.
The Greenstar 1000 is a great heating choice for smaller homes and those on a budget. It’s especially suitable for flats, apartments, and small houses where a bigger boiler isn’t needed.
Worcester Bosch Greenstar 1000 Specifications
| Specification | Greenstar 1000 24kW | Greenstar 1000 30kW |
|---|---|---|
| Boiler type | Combi | Combi |
| Fuel | Natural gas | Natural gas |
| Space-heating efficiency | 93% | 93% |
| ErP heating rating | A | A |
| Maximum CH output | 24kW | 24kW |
| Hot-water output | 24kW | 30kW |
| Hot-water flow rate at 35°C ΔT | 9.8 litres/min | 12 litres/min |
| Dimensions | 655 × 395 × 285mm | 655 × 395 × 285mm |
| Sound power level | 52dB(A) | 52dB(A) |
| Standard guarantee | 5 years* | 5 years* |
*Guarantee conditions apply.
What Are The Main Greenstar 1000 Selling Points?
Just because a boiler is affordable doesn’t mean it’s good value.
The real question is whether the Greenstar 1000 gives you the features you need without charging you for extras you won’t use.
It’s Designed With Affordability In Mind
Perhaps the biggest selling point is also the most obvious.
The Greenstar 1000 was created as Worcester Bosch’s budget-focused boiler.
It’s a good choice for people who want a Worcester Bosch boiler but don’t need the extra features of pricier models.
It’s 93% Efficient
Both Greenstar 1000 models have a 93% ErP space-heating efficiency and carry an A rating for heating.
Jargon Buster: ErP rating
The Energy-related Products (ErP) directive is a regulatory framework designed to drive improvements in the efficiency and performance of heating products. An ‘A’ rating signifies excellent energy conversion, helping to keep heating bills lower.
Modern condensing boilers recover heat that would otherwise disappear through the flue, helping them use gas more efficiently than many older boilers.
However, replacing your boiler won’t automatically cut your heating bills, since things like usage, insulation, controls, and energy prices also play a role.
Still, swapping an old, inefficient boiler for a modern condensing one can help lower unnecessary energy use.
It Fits Inside A Kitchen Cupboard
Space is just as important as price, especially in smaller homes.
The Greenstar 1000 measures: 655mm high × 395mm wide × 285mm deep.
Worcester Bosch specifically designed it to fit inside a standard 300mm-deep kitchen cupboard.
That makes it useful when you don’t want your boiler becoming the star attraction of your kitchen.
It’s Relatively Lightweight
The Greenstar 1000 weighs around 26kg, with Worcester Bosch describing it as suitable for a one-person lift.
This mainly benefits the installer, since you probably won’t notice the weight once the boiler is on the wall.
But easier installation and servicing are important, since a boiler isn’t something you can just install and ignore for years.
Front-Access Servicing
Worcester Bosch has designed the Greenstar 1000 so that important components can be accessed from the front.
The heat exchanger, pressure-relief valve and other components have been positioned with maintenance and servicing in mind.
Again, this may not sound exciting.
But neither is paying an engineer to dismantle half your kitchen cupboard just to reach something.
Being easy to service really does matter.
An Engineer’s View
The Greenstar 1000’s compact footprint and front-access layout make it a dream to install and service in tight spaces like kitchen cupboards. It really proves that you do not need to sacrifice maintenance convenience when opting for a budget-friendly boiler.
– Matthew Powell, Gas Safe Engineer
Smart Control Compatibility
The Greenstar 1000 is compatible with Worcester Bosch’s EasyControl smart heating controls.
Smart heating controls can give homeowners more precise control over when their heating operates and at what temperature.
For households looking to manage energy use, having better control can be just as important as the efficiency rating on the boiler.
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Greenstar 1000 24kW Or 30kW: Which Do You Need?
It’s easy to think that a higher number always means a better boiler.
That’s not always true.
Both Greenstar 1000 models provide up to 24kW of central-heating output. The significant difference is the amount of hot water they can produce.
The 24kW Greenstar 1000 offers a hot-water flow rate of approximately 9.8 litres per minute at a 35°C temperature rise.
The 30kW version increases this to approximately 12 litres per minute.
In practice, the 30kW model is better if your home needs more hot water.
But when choosing a boiler, you need to consider your home’s size, number of radiators, bathrooms, and how much hot water you use. Bigger isn’t always better.
What Should You Consider Before Choosing The Greenstar 1000?
Price is important, especially if you didn’t plan for a boiler replacement this month.
But it shouldn’t be your only concern.
Before choosing any new boiler, think about:
The Size Of Your Home
The Greenstar 1000 is primarily targeted towards smaller properties.
A larger home with substantial heating requirements may need a different boiler or heating system.
How Much Hot Water You Use
Combi boilers heat water directly rather than storing it in a separate hot-water cylinder.
This setup works well for many homes, but if you have several bathrooms or need a lot of hot water at once, you might need a different system.
Your Water Pressure And Flow Rate
A powerful combi boiler can’t manufacture water that isn’t arriving at the property.
So, you need to check your mains water pressure and flow rate when picking a combi boiler.
Where The Boiler Will Be Installed
The Greenstar 1000’s small size makes it a good choice for homes where space is limited.
However, you still need to consider installation needs, pipework, flue position, and space for servicing.
Controls
Remember to think about your heating controls.
Modern thermostats and controls help your heating system respond better to when your home really needs warmth.
Installation Cost
The boiler is just one part of the total replacement cost.
Installation might also include changing the flue, updating pipework, cleaning the system, adding filters, controls, and other work, depending on your current setup.
That’s why it’s better to compare full installation quotes instead of just looking at boiler prices.
Worcester Bosch Greenstar 1000 Vs Greenstar 4000
The Greenstar 1000 isn’t the only Worcester Bosch combi boiler worth considering.
Further up the range is the Worcester Bosch Greenstar 4000, which we’ve covered in our separate review.
The Greenstar 1000 is positioned as Worcester Bosch’s more budget-conscious option, particularly for smaller homes. The Greenstar 4000 sits higher in the range and offers a different set of specifications and features.
That doesn’t automatically mean you need the more expensive boiler.
If the Greenstar 1000 comfortably meets your home’s heating and hot-water requirements, paying more simply to move further up Worcester Bosch’s range may not be necessary.
Is The Worcester Bosch Greenstar 1000 A Good Boiler?
For the right home, there is a lot to like about the Greenstar 1000.
It’s compact, A-rated, relatively lightweight and backed by one of the UK’s best-known boiler manufacturers.
More importantly for this particular model, Worcester Bosch hasn’t tried to disguise what it is.
The Greenstar 1000 is a budget boiler aimed primarily at smaller homes.
And that’s not necessarily a criticism.
Not everyone needs the most powerful boiler, the longest feature list, or the most expensive model.
Sometimes, you just need an efficient boiler that fits your home and your budget.
The Greenstar 1000 could be a great fit for that need.
Find The Right Boiler For Your Home With WarmZilla
The Worcester Bosch Greenstar 1000 may seem like a good choice, but picking a boiler is about more than just the brand name.
You should think about your home’s size, number of bedrooms and bathrooms, hot water needs, current heating system, and budget.
That’s where WarmZilla comes in.
Just fill out our quick online boiler survey, answer a few questions about your home, and we’ll show you the best boiler options for your heating and hot water needs.
Frequently Asked Questions
Is The Worcester Bosch Greenstar 1000 A Good Boiler?
For smaller homes, the Greenstar 1000 offers a strong combination of affordability, compact dimensions and 93% space-heating efficiency. However, whether it’s suitable depends on your property’s heating and hot-water requirements.
What’s The Difference Between The Greenstar 1000 24kW And 30kW?
Both provide up to 24kW of central-heating output. The main difference is hot water. The 24kW model delivers around 9.8 litres per minute, while the 30kW reaches around 12 litres per minute at a 35°C temperature rise.
What Size Home Is The Worcester Bosch Greenstar 1000 Suitable For?
Worcester Bosch positions the Greenstar 1000 primarily for smaller properties, including flats, apartments and smaller houses.
The correct model should still be chosen according to your radiators, bathrooms, water flow rate, and typical hot-water demand.
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