Glow-worm Compact Combi Boiler Cost with Installation
The Glow-worm Compact combi costs between £1,450 and £2,050, including installation.
The boiler unit alone costs, on average, between £650 (24kW) and £750 (28kW), with installation costs up to £1,300.
The Compact combi is just that – a compact, efficient combi boiler that fits seamlessly into your home. It is a modern, user-friendly option for smaller homes where space is limited; its compact dimensions allow it to fit a kitchen cupboard, offering reliable heating and hot water without disrupting the living space.
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Discover more about this boiler’s specifications below:
| Glow-worm Compact combi Product Table | |||
|---|---|---|---|
 | Available outputs | 24kW | 28kW |
 | Type | Combi | Combi |
| Fuel | Gas | Gas | |
| Condensing | Yes | Yes | |
| Efficiency rating (%) | 92 | 93 | |
| ErP | A | A | |
| LPG compatible | Yes | Yes | |
| Standard guarantee | 5 years* | ||
| Max output (kW) | 24 | 28 | |
| Flow rate (l/min) | 9.9 | 11.5 | |
| Mounting | Wall-mounted | ||
| Dimensions (mm) | 626 x 400 x 270 | ||
| Typical price (incl. VAT) | £650 | £750 | |
| Typical installation cost (incl. VAT) | £800 – £1,300 | ||
| Total cost | £1,450 – £2,050 | ||
*Terms and conditions apply.
Glow-worm Compact combi overview
The Glow-worm Compact combi boiler is designed for homeowners who need a reliable, affordable boiler that fits neatly into tight spaces. Measuring just 626mm high, it’s one of the most compact combi boilers in its class, making it ideal for cupboard installations in kitchens, flats, and smaller homes.
Despite its size, the Compact combi delivers dependable performance and high efficiency. Both models are ErP A-rated, helping reduce energy waste and keep running costs low. As an all-in-one combi boiler, the Glow-worm Compact provides both central heating and hot water directly from the mains, without the need for a separate hot water cylinder or storage tank.
| Glow-worm Compact Combi Range | |||
|---|---|---|---|
| Model output size | House size | Bathrooms | Radiators |
| 24kW | Flats, small homes 1 to 3 bedrooms | 1 | Up to 10 |
| 28kW | Small or medium homes 3 to 4 bedrooms | 1 | Up to 15 |
As the Glow-worm Compact combi delivers hot water at around 9.9-11.5 litres per minute, it is not recommended for homes with multiple bathrooms or where hot water is likely to be used simultaneously. However, for smaller households the Compact combi offers an efficient, space-saving heating solution at a very competitive price point.
So, if you’re working with a property that includes a bath, we recommend the 28kW model to meet your hot water demands, whilst the 24kW model works well for properties with a single shower.
💡WhatPrice Tip: A bigger boiler output isn’t always the right choice. If you have lower hot water usage, then a higher output model can actually be less efficient and increase running costs. It’s best to ensure that the output you choose is matched with your hot water demand.
Key benefits at a glance
- ErP A-rated efficiency (92–93%) for lower energy bills
- Compact, cupboard-friendly size
- Quiet operation, suitable for kitchens and living spaces
- Simple, user-friendly controls
- Compatible with smart thermostats
- LPG-compatible for off-gas properties
- Built-in frost protection
- 5-year manufacturer warranty
Glow-worm Compact combi technical specifications
The Glow-worm Compact combi is designed as a practical, affordable boiler for smaller properties. Whilst it doesn’t include some of the more premium features (such as extended manufacturer warranties, built-in Wi-Fi controls, or weather compensation) found on higher-end models, it offers solid efficiency, dependable heating performance, and straightforward operation at a competitive price point.
Output and efficiency ratings
The 24kW and 28kW output options on the Glow-worm Compact combi both provide instant hot water on demand. And at a 92-93% efficiency, the vast majority of fuel used is converted into usable heat.
An ErP A-rated boiler like the Compact combi is ideal for keeping energy bills lower and reducing fuel waste, compared with older and less efficient boilers. The Compact combi reuses heat that would otherwise be lost through the flue. Condensation management and necessary safety valves help it achieve its high efficiency rating
Dimensions
Measuring 626mm in height, 400mm in width, and 270mm in depth, the Compact combi is one of the smallest options in its class.
With features such as a 25mm spacer frame, pipework can run neatly behind the boiler while still fitting within a standard 300mm cupboard. This allows for discreet placement and fast installation in tight spaces.
Components included
The Glow-worm Compact combi boiler includes a stainless steel domestic hot water heat exchanger, chosen for durability and corrosion resistance. This helps maintain performance over time and supports long-term reliability, especially in areas with harder water.
With a user-friendly digital display and controls, homeowners can make everyday adjustments easily, including: setting heating temperature; adjusting hot water demand; and viewing operating information.
The Compact combi also includes built-in frost protection. When the boiler water temperature falls below 8°C, the internal pump operates automatically. If temperatures drop further – to around 5 °C – the burner will activate to gently warm the system, with a timer periodically checking temperature to switch off once safe operating temperatures are restored. This helps safeguard the boiler during colder weather making it dependable for kitchens and utility rooms or properties left unoccupied for short periods in winter.
To prevent overheating, the boiler also has an overheat safety thermostat that shuts the boiler down if internal temperatures exceed safe limits.
Whilst a smart thermostat isn’t included, the boiler is compatible with Glow-worm’s MiSet, MiGo Select, and Climastat Select controls for advanced scheduling and remote operation.
Prices and installation costs
The Glow-worm Compact combi boiler typically costs £650–£750 for the boiler unit alone, depending on the output size. This includes listings for boilers which come as ‘packs’ with a flue included – typically costing £100 for a standard flue. A flue is a crucial part of the boiler that channels harmful gases outside. Flues can exit from an external wall or vertically, through the roof. Roof flues can be significantly more expensive (at over £550) as installation can be tricky.
Installation costs are usually around £1,200, bringing the total installed cost to around £1,850–£1,950.
| Glow-worm Compact Combi Costs | ||
|---|---|---|
| Output size | Unit cost (incl. flue) | Total (incl. installation) |
| 24kW | £650 | £1,850 |
| 28kW | £750 | £1,950 |
These prices are based on our research and actual boiler prices submitted to WhatPrice by homeowners. However, total costs will largely depend on the complexity of your boiler replacement and the daily rates of your installer.
To get an accurate price, it’s always best to request quotes from at least 3 Gas Safe registered installers. They will give you expert advice on the right boiler for your home, and you can compare quotes to get the best deal.
Further, you can use the WhatPrice Boiler Cost Calculator to get a guide price for your installation.
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Warranty and support
The Glow-worm Compact combi comes with a free 5-year out-of-the-box manufacturer warranty, providing peace of mind from the day of installation.
In order for the warranty to be valid, certain terms and conditions apply: the boiler must be installed by a Gas Safe registered engineer; it must be registered with Glow-worm within 30 days after installation; annual servicing must be carried out in line with manufacturer requirements.
The warranty covers manufacturing faults and component failures, but does not cover general wear and tear, damage caused by system debris, or issues arising from incorrect installation or lack of servicing.
Glow-worm provides UK-based customer support and a nationwide service network, offering assistance with servicing, repairs, and technical advice throughout the boiler’s lifespan.
Installation information
When choosing a new boiler, it is useful to know what to expect from the installation process. Installation costs for the Glow-worm Compact combi are typically around £1,200, depending on the installer, local rates, your current heating system, and any additional parts needed.
What to expect on installation day
To get an idea of what’s involved in a boiler installation, here’s a rundown of the main steps:
- Preparation and checks
Your engineer will inspect the installation area, confirm pipework and flue routes, and check the pre-existing system to plan for how that will be removed. - Removing the old boiler
The existing boiler will be safely disconnected from gas, water, and power supplies. Switching from a system or regular boiler to a combi, any tanks and cylinders will need to be removed. - Installing the new boiler
The Glow-worm Compact combi is wall-mounted and designed for fast installation. If the new boiler is fitted in the same location as the old one, pipework changes are often minimal. If it’s being relocated, additional pipe or wiring adjustments may be needed. - Configuration and controls
Once installed, the system is filled and pressurised. Your engineer will test radiators, hot water flow, and safety controls, and set up any compatible thermostats. - Switch on and handover
The installer will carry out final checks, demonstrate how the boiler is controlled, and complete any necessary paperwork such as registering to activate the manufacturer warranty.
Additional work might be required in some cases e.g. if there are significant steps needed when upgrading pipework or relocating the boiler. This is something your installer will clarify before work begins – giving you an idea of timeline and any extra costs associated with the installation.
Do you need a system flush or filter?
Under UK Building Regulations, new boiler installations must include adequate system cleaning and protection. In practice, this requirement is typically met by fitting a magnetic system filter. When installing a new boiler, your engineer may also recommend carrying out a ‘system flush’.
These additional precautions help keep the system clean, protect internal boiler components, and support trustworthy performance in the long-run.
A system flush is carried out before the new boiler is installed. Using a specialist cleaning solution to remove sludge and debris before the new pipework is installed. This ensures your radiators heat more evenly and reduces the risk of internal blockages.
A filter is fitted to the system to capture rust and dirt particles before they circulate through the boiler. It can play an important role in protecting internal components and supporting boiler longevity.
As a general guide, a system flush typically costs £350-£800, while a filter may cost £65-£300, depending on your system and installer.
Finding a Gas Safe registered engineer
In the UK, gas boiler installations must legally be carried out by a Gas Safe registered engineer. This ensures the work meets safety regulations and is completed to the right standard.
Before choosing an installer, it’s a good idea to gather quotes from several Gas Safe registered engineers. This allows you to compare pricing, experience, and recommendations, helping you find the right installer.
You can also use the WhatPrice quote service to be matched with vetted, Gas Safe registered installers in your area.
Reviews and ratings
Glow-worm is a long-established boiler manufacturer in the UK, with a score of 4.4 out of 5 stars on Trustpilot. Reviews of Glow-worm boilers generally reflect good value for money, practical design choices, and trusted day-to-day performance, particularly in smaller homes.
Feedback specific to the Glow-worm Compact combi follows this, but with some drawbacks to consider.
Positive reviews
One of the most frequently praised aspects of the Glow-worm Compact combi is its space-saving design. Reviewers often describe it as a “brilliant little boiler” that fits neatly into standard kitchen cupboards, making it especially well suited to flats and smaller houses where space is limited.
Quiet operation is another recurring positive. Many users note that the boiler runs very quietly in the background, to the point where it’s barely noticeable during normal use – an important consideration for kitchen or open-plan installations.
Homeowners also report fast and consistent hot water delivery for everyday use. Showers and taps are said to warm up quickly and maintain a consistent temperature.
Ease of use features strongly in feedback, with reviewers describing the controls as simple and intuitive. Those using compatible Glow-worm smart controls, such as the MiGo system, highlight the convenience of making remote heating adjustments via an app.
Customers upgrading from older boilers frequently mention improved efficiency, noting that their homes heat up more quickly and, in some cases, that energy bills are lower following installation.
Negative reviews
There are occasional reports of servicing or repair needs earlier than expected, though these are not widespread. Where issues are mentioned, Glow-worm’s customer support is often described as responsive in resolving problems.
Some reviewers also note limitations in hot water performance at higher demand, particularly with the 24kW model. Filling a bath can take longer, and performance may be stretched if hot water and central heating are required at the same time. For this reason, we suggest that the 28kW Compact combi is generally better suited to homes with a bath, whilst the 24kW model is best matched to flats or properties with a single shower and moderate usage.
A smaller number of users point out that the Compact combi lacks some premium features found on higher-end boilers, such as built-in smart controls or longer standard warranties. However, many reviewers view this as an acceptable trade-off given the boiler’s lower upfront cost and practical focus.
Overall, independent reviews suggest that the Glow-worm Compact combi is regarded as a reliable, space-efficient, and budget-friendly boiler – performing best when installed in the types of properties it’s suited for.
How the Glow-worm Compact combi compares
Choosing the right boiler often comes down to balancing price, size, warranty, and performance. The Glow-worm Compact combi sits in the compact, budget-friendly end of the market, making it a popular choice for smaller properties.
Its closest competitors are the Ideal Logic Max Combi2, Baxi 400 Combi 2.1, and Worcester Bosch Greenstar 4000, targeting similar property types but differing in features, warranties, and upfront cost.
In the table below, we’ve compared these models to help you get an idea of how the Glow-worm Compact combi versus competitors.
| Glow-worm Compact Combi Comparison Table | |||
|---|---|---|---|
| Make and Model | Pros | Cons | Cost (excl. installation) |
| Glow-worm Compact Combi | Very compact footprint Competitive pricing, budget-friendly Stainless steel heat exchanger Quiet operation Built-in frost protection LPG compatible Glow-worm scores 4.4/5 on Trustpilot | Shorter standard warranty Limited output range (24kW, 28kW) Fewer premium smart features as standard | £750 |
| Baxi 400 Combi 2.1 | 94% energy efficiency (ErP A-rated) Compact build for easy install Whisper-quiet operation Long-lasting brass hydraulics and a stainless steel heat exchanger Lower cost and value for money Baxi scores 4.6/5 on Trustpilot | 5-year standard warranty – no options to extend Output sizes are not suitable for very high hot water demand (24kW, 30kW and 36kW) Features are basic compared to other Baxi series | £770 |
| Ideal Logic Max Combi2 | 10-year standard parts and labour guarantee 94% energy efficiency (ErP A-rated) Compact size Includes system filter Built-in frost protection Competitive pricing Ideal scores 4.8/5 on Trustpilot | Occasional issues with customer service Not as quiet as other brands | £1,100 |
| Worcester Bosch Greenstar 4000 Combi | 7-year standard guarantee (extendable to 10 years) 94% efficiency Quiet Mark certified Modern design Built-in Wifi (Bosch EasyControl) 4.6/5 on Trustpilot | Fewer output sizes (25kW, 30kW) Aluminium heat exchanger, less durable Some features are only available with premium controls | £1,200 |
Keep in mind that this comparison focuses on key features, but there may be other details that matter more for your home. For personalised guidance on choosing the right boiler, we recommend speaking with a Gas Safe registered engineer.
Final thoughts – is the Glow-worm Compact combi right for you?
The Glow-worm Compact combi is a strong choice for small homes and flats, particularly properties with one bathroom and moderate hot water demand. Its compact dimensions make it ideal for cupboard installations, whilst its ErP A-rated efficiency helps keep running costs under control.
A practical all-in-one combi boiler, the Compact provides heating and hot water directly from the mains without the need for a separate cylinder or tank. With straightforward controls, quiet operation, and competitive pricing, it’s well suited to homeowners looking for a reputable boiler.
It’s important to note that the Compact combi is not suited for homes with multiple bathrooms. With outputs of 24kW and 28kW, it performs best in single-bathroom properties, where hot water is used one outlet at a time.
When compared with similar models, the Glow-worm Compact combi stands out for its affordability and small size. Alternatives such as the Ideal Logic Max Combi2 offer longer warranties, whilst models like the Worcester Bosch Greenstar 4000 provide a more premium finish at a higher upfront cost. The Compact combi remains a very sensible option for those prioritising value, space-saving design, and dependable everyday performance.
To make sure you make the right choice for your home, it’s always best to consult with a Gas Safe registered engineer who can best assess your hot water needs and recommend the most suitable boiler for you.
FAQ
What is the ideal boiler pressure for the Glow-worm Compact combi?
The recommended system pressure is typically between 1.0 and 1.5 bar when the system is cold, which is the ideal operating range for the Compact combi. Pressure will naturally increase when the heating is running but should not rise above 2.5 bar. If the pressure rises too quickly or regularly exceeds this level it may indicate an issue with the filling valve or pressure system. Persistent problems should be checked by a Gas Safe registered engineer.
What smart thermostat options are compatible with the Glow-worm Compact combi?
The Compact combi is compatible with Glow-worm controls such as MiSet, MiGo Select, and Climastat Select, allowing for improved scheduling and remote heating control. Other compatible thermostats may also be used, depending on system setup.
For homeowners who prefer simple controls, an optional analogue clock can be fitted without removing the boiler case, offering straightforward timed heating without the need for smart technology.
What servicing does the Glow-worm Compact combi require?
To maintain warranty validity, the boiler must be serviced annually by a Gas Safe registered engineer. A typical service includes safety checks, inspection of key components, pressure checks, and ensuring the flue and condensate systems are functioning correctly.
Is the Glow-worm Compact combi hydrogen-ready?
The Glow-worm Compact combi is LPG compatible, but it is not currently marketed as hydrogen-ready for blended gas supplies.
What size home is the Glow-worm Compact combi suitable for?
The 24kW and 28kW models are best suited to small to medium sized homes with one bathroom. The 28kW model is generally recommended where a bath is used regularly, while the 24kW version is ideal for flats with a shower and lower hot water demand.
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- Compare & Save up to 30%
- New Boiler Installed Fast
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