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Last updated: 6th March, 2024


Glow Worm Combi Boiler Costs

Glow Worm Combi Boiler Costs

Key takeaways

  • Glow Worm combi boilers offer a compelling blend of efficiency and value, making them a popular choice among UK homeowners.
  • The cost of a Glow Worm combi boiler will vary, influenced by model selection, installation complexity, and individual household needs.
  • Glow Worm's range provides a diversity of options, ensuring there’s a boiler to match the efficiency and performance expectations of various consumers.

A combi boiler, or combination boiler, is a high-efficiency water heater and a central heating boiler united in one compact unit.

In recent years, the demand for efficient and cost-effective home heating solutions has led to a rise in popularity for combi boilers in the UK market. Among the myriad of options available to consumers, Glow Worm combi boilers stand out for their balance of efficiency, performance, and affordability

As heating costs continue to climb, many homeowners are opting for these boilers due to their capacity for providing both heating and hot water from a single unit, eliminating the need for a separate hot water tank.

The cost analysis of a Glow Worm combi boiler depends on various factors, including the model chosen, its size, and the specific requirements of the home. For example, prices can vary depending on whether it's a simple replacement of an existing combi boiler or a full system upgrade. 

Despite these variations, Glow Worm remains competitive, with a range of models each designed to suit different home sizes and budgets, all while maintaining high efficiency ratings and a reputation for reliability.

Understanding Combi Boilers

Combi boilers, known for their compact size and dual functionality, provide central heating and hot water without the need for a separate water tank.

What Is a Combi Boiler?

A combi boiler, or combination boiler, is a high-efficiency water heater and a central heating boiler united in one compact unit. These boilers heat water directly from the mains whenever a tap is turned on, which means there's no need for a hot water storage cylinder or a cold water storage tank in the roof space. They are particularly suited to homes with limited space and smaller water demands.

Benefits of Combi Boilers

Combi boilers offer various advantages that contribute to their popularity in the UK:

  • Space-Saving: Their compact size frees up space in a home, as no separate hot water cylinder or cold water tank is required.

  • Cost-Effective: Installation tends to be less complex and therefore cheaper due to fewer components, and they can also reduce energy bills given their energy efficiency.

  • Convenience: Hot water is provided on demand with a combi boiler, ensuring speedy access to heating and showers without the wait for a tank to refill.

  • Energy Efficiency: Typically, combi boilers are considered to be more energy-efficient as they only heat water that is required at the time, helping to lower carbon emissions.

Their capacity to cater to both hot water and heating needs simultaneously, without forfeiting energy efficiency, makes combi boilers a preferred choice for many households.

Exploring Glow-Worm's Combi Boiler Range and Key Features

Glow-Worm's diverse combi boiler range is renowned for integrating advanced technology with performance. Their compact designs and energy efficiency make them a reliable choice for UK homeowners.

Compact Combi Boiler

Glow-Worm's Compact Combi Boiler is tailored for modern homes, offering two output choices: 24 or 28 kW. Customers appreciate the user-friendly LCD display and compact design, which is ideal for space-saving installations. Being ErP A-rated, it also promises lower energy bills.

Compact Combi LPG Boiler

Designed for properties not connected to the mains gas network, the Compact Combi LPG Boiler rendition delivers the same efficiency and features as the gas model. These boilers provide a sustainable alternative without sacrificing performance.

Energy Combi Boilers

The Energy Combi Boilers series boasts an ErP A-rating for heating and water, signifying superior energy performance. Their modulating Grundfos pump adapts the boiler's energy usage, striking a balance between energy use and comfort.

Ultimate₃ Combi Boilers

The Ultimate₃ Combi Boiler is armed with a 30kW heating output, making it apt for mid-sized properties. It shines with high efficiency and comes equipped with the technology needed to ensure reliable heating and hot water on demand.

Easicom₃ Combi Boilers

Glow-Worm's Easicom₃ Combi Boilers are part of an affordable range that doesn't compromise on quality. Designed with straightforward controls and robust components, these boilers are suitable for a wide array of UK homes.

MicraCom Boiler

The MicraCom Boiler is notable for its diminutive size and stainless steel heat exchanger. Despite its compact footprint, it is power-packed, ensuring high performance and an easy-to-use interface perfect for cupboard installation.

Analysis of Glow-Worm Combi Boiler Costs

With a keen eye on affordability and value for money, exploring Glow-Worm combi boiler costs reveals a landscape influenced by various factors, from boiler specifications to installation complexities. Consumers compare prices meticulously, seeking boilers that promise not only competitive pricing but also long-term savings on energy expenditures.

Price Factors for Glow-Worm Boilers

The cost of a Glow-Worm combi boiler can be influenced by several distinct variables:

  • Boiler output: For a dwelling of average size, such as a 3-4 bedroom home, a 30kW boiler like the Glow-Worm Ultimate3 is suitable. The prices scale with output; a higher-capacity 35kW model will cost more.

  • Installation costs: These can diverge markedly based on location, the condition of the existing heating system, and any additional work necessary for the fitting.

  • Energy efficiency: The higher the efficiency, exemplified by an ErP A-rating, the less energy consumed. This translates into potential long-term savings, a key factor in the boiler's overall value.

  • After-sales support: The provision of warranties and customer service can affect the cost while offering peace of mind.

Costs of specific models are subject to change and vary by supplier, but expect to budget around £695 for lower output models, reaching upwards of £770 for higher capacity options, excluding fitting charges.

Comparing Prices and Value

Comparing Glow-Worm boilers on costs alone oversimplifies what homeowners should consider:

  • Efficiency and savings: While the initial cost is important, efficient models like the Glow-Worm Energy 30c can reduce long-term energy bills, enhancing the value for money.

  • Brand satisfaction: Customer satisfaction often reflects in repeat business and recommendations. Most Glow-Worm customers are willing to advocate for the brand, indicating that the boilers represent good value.

  • Comparative market prices: When set against rivals in the market, Glow-Worm boilers consistently present competitive pricing, especially when considering their energy efficiency and the subsequent cost-saving potential.

Homeowners are advised to gather no-obligation quotes from multiple suppliers to best gauge the market and make an informed decision based on individual requirements and budgets.

Efficiency and Rating

Glow Worm combi boilers stand out due to their superior energy efficiency ratings and high performance in output. They have been recognised for their reliability in home heating, providing both hot water and central heating effectively.

Energy Efficiency Rating

Glow Worm combi boilers typically come with an ErP A-rating, which represents a high level of energy efficiency. This rating is an indication of the boiler's ability to convert energy to heating with minimal wastage. The ErP rating system is designed to help consumers compare the energy performance of different products on an easy-to-understand scale from A++ to G, with A++ being the most efficient.

  • Glow Worm Energy 25c - A-rated

  • Glow Worm Energy 30c - A-rated

  • Glow Worm Energy 35c - A-rated

Output and Performance

The range of outputs offered by Glow Worm combi boilers serves various household sizes, ensuring the right fit for any home. A 30kW model, like the Glow Worm Ultimate₃, is typically well-suited for average-sized UK domiciles, such as 3-4 bedroom semi-detached houses.

  • 25kW Output: Ideal for small homes with lower heating demands.

  • 30kW Output: Offers a balance of performance and efficiency for median-sized homes.

  • 35kW Output: Accommodates larger properties with greater heating requirements.

The performance is not solely determined by output but also by the boiler's ability to maintain its efficiency over time. Glow Worm's aluminium heat exchangers are designed for longevity and contribute to maintaining the energy efficiency of the combi boiler throughout its operational life.

Installation Considerations

When selecting and installing a Glow Worm combi boiler, homeowners need to consider not only the size and fit but also the intricacies of the process, including regulations and costs.

Choosing the Right Size

The dimensions and output of a boiler should correspond to the household's heating and hot water demands. A small flat may require a boiler with a lower kW output, typically around 24kW, which could be around £550, whilst a larger home might necessitate a 35kW boiler, closer to £780. Selecting the perfect fit ensures efficiency and prevents unnecessary expenditure on a unit that's either too powerful or inadequate for one's living space.

Installation Process

The installation must adhere to Gas Safe regulations, which dictate that only certified engineers are permitted to install gas boilers. The complexity of the installation process can influence costs; a straightforward replacement is generally more affordable. Total installation costs, including the price of the unit itself, can range from approximately £2,200 to £4,000. Prior to installation, the chosen engineers will assess the site to ensure compatibility and discuss any necessary preparatory work, ensuring the boiler integrates seamlessly into the existing system.

It's worth noting that while the process is structured and involves several technical steps, a Glow Worm combi boiler is renowned for being relatively easy to install compared to other brands. Engineers typically manage the installation within a day, barring any unforeseen complications. This efficiency can be attributed to their compact design and user-friendly interfaces, streamlining both installation and future maintenance.

Running Costs and Savings

Investing in a new Glow Worm combi boiler presents homeowners with the prospect of reducing energy bills and enjoying long-term reliability. Here's how these benefits manifest:

Reducing Energy Bills

Glow Worm combi boilers are designed to be energy-efficient, an attribute that warrants the potential for homeowners to see a decrease in their energy expenditures. For instance, upgrading from a boiler that's more than a decade old to a modern Glow Worm model can lead to annual savings. The Energy Saving Trust provides estimates that illustrate potential savings in running costs with a new energy-efficient boiler.

  • Old Boiler Efficiency: Approximately 60-70%

  • New Glow Worm Boiler Efficiency: Up to 94%

By transitioning to a newer model, homeowners could notably diminish the energy required for heating and hot water, hence cutting down on their energy bills.

Long-Term Reliability

When it comes to Glow Worm boilers, reliability equates to fewer repair needs and, consequently, reduced maintenance costs over time. A reliable combi boiler minimises the chance of unexpected breakdowns, supporting a cost-effective and worry-free operation.

  • Annual Maintenance Costs: Vary based on warranty and service plans

  • Expected Boiler Lifespan: Up to 15 years with proper maintenance

Owners of Glow Worm combi boilers can anticipate consistent performance, which underscores the importance of regular servicing to maintain their system's longevity and efficiency.

Warranty and Manufacturer Support

Glow-worm's provision of warranties and their customer support structure are pivotal in delivering peace of mind to their users. Those considering a combi boiler will find that Glow-worm provides a range of warranty options catered to different models and customer needs, along with a dedicated service network.

Glow-Worm's Warranty Offers

Glow-worm combi boilers come with a manufacturer's warranty that can vary extensively in duration. Standard warranties for their range of combi boilers start from:

  • 3 years for models such as the Easicom3 24kW

  • 5 years for the Betacom4 range

  • Up to an impressive 15-year guarantee for the Energy 35 Store model

These warranties cover boiler repair and fault due to manufacturing defects within the specified periods starting from the installation date. For customers who find extended guarantees important, Glow-worm sometimes offers the option to extend their warranty. This extended warranty can cover periods up to 15 years, as is the case with certain models in the Energy series, highlighting Glow-worm's confidence in their products.

It's noteworthy that to maintain the validity of the warranty, an annual boiler service by a qualified engineer is required. Glow-worm is part of the Vaillant Group, which could contribute to the strong backing and reliability of their warranty offers.

Customer Service and Maintenance

When it comes to customer service, Glow-worm aims to provide streamlined assistance through various channels. For technical support, users can contact the manufacturer directly via a support line which, as an example, might be found as 0330 100 3142 in one of the snippets.

In terms of servicing, Glow-worm encourages regular maintenance, which not only preserves the validity of the warranty but also assuages the likelihood of untimely disruptions due to boiler malfunctions. Servicing includes a series of checks and tests performed by authorised engineers to ensure the boiler operates at peak efficiency. Additionally, should a boiler repair be necessary, the service network is poised to respond with promptness, denoting the importance placed on customer satisfaction and product reliability.

Additional Features and Technologies

Glow Worm combi boilers are equipped with cutting-edge features that enhance efficiency and user experience. These boilers utilise condensing technology and can be adapted to use LPG, catering to the diverse requirements of different households.

User Controls and Functionality

Glow Worm combi boilers boast an array of user controls that offer simplicity and convenience. The boilers' interfaces include digital displays that provide real-time information about the system's operation. They offer users the ability to precisely adjust temperature levels, programme heating schedules, and manage hot water supply with ease. This functionality is often accessible remotely via smart thermostats, which translates into better control and potentially lower fuel consumption over time.

  • Temperature Control: Precise adjustment features.

  • Programmable Schedules: Customisable heating plans.

  • Remote Access: Control via smart devices for enhanced convenience.

Safety and Regulations

Safety is paramount in the design of these boilers. Glow Worm combi boilers adhere strictly to UK safety and regulatory standards to ensure peace of mind for consumers. They incorporate features such as automatic shutdown mechanisms in case of malfunction and mandatory pressure relief valves. These boilers also support safe fuel combustion, reducing the risk of carbon monoxide hazards and complying with ErP regulations for energy-related products.

  • Automatic Shutdown: Prevents operation during faults.

  • Pressure Relief Valves: Essential for boiler integrity and safety.

  • Carbon Monoxide Safety: Equipped with measures to prevent hazardous leaks.

Consumer Opinions and Reviews

In the landscape of heating solutions, Glow-worm combi boilers are a topic of active discussion among consumers. Notably, the Trustpilot platform features a multitude of customer service reviews. Users have expressed satisfaction with recent Glow-worm boiler installations, highlighting efficiency improvements and reductions in utility bills. It's evident that the brand's promise of longevity and performance is a recurring theme in customer feedback.

Glow-worm also operates a scheme known as Club Energy. This installer loyalty programme has attracted professionals, evidentially fostering a network of Club Energy Partners. Through this scheme, installers gain access to rewards and business support, enhancing their service delivery. The mutual benefits seem to affirm the strength of Glow-worm's support for professionals in the field.

Within the realm of reviews, satisfaction levels are high, as are the recommendations to peers, according to a survey highlighted by a consumer reporting agency. While this speaks volumes, it is worth noting that the likelihood to recommend tracks marginally below the rating for satisfaction itself.

  • Satisfaction: Highly rated by customers.

  • Recommending: Majority likely to endorse Glow-worm.

  • Efficiency: Acknowledged improvement on energy bills.

  • Club Energy: Loyalty scheme providing tangible installer benefits.

This snapshot of consumer opinions underscores a clear, overarching narrative: Glow-worm boilers garner positive reviews overall, amplified by the installer support and reliability imparted through the Club Energy programme. This adds a layer of assurance for prospective customers, suggesting that purchasing a Glow-worm combi boiler could be a worthwhile investment.

iHeat New Boiler Costs

Boilers can be a daunting purchase for many people as they’re an appliance with a lot of responsibility, providing heat for you and your family is something you want to get right. Boilers aren’t exactly a quickly disposable item either, potentially lasting you a decade.

Boiler costs can be split into two segments: the first is the actual boiler itself (unit price), and the second is the cost of the boiler being installed (set up) in your property by an expert engineer. 

Here at iHeat, we want to remove all of this undue stress and make the decision making process of upgrading to a new central heating system, as easy as possible.

Boiler costs can vary depending on a number of factors including their brand, model, fuel, output, warranty, labour and installation type. Typically a new boiler will cost between £1,845 and £3,500, below is a list of average boiler installations offered by iHeat (guide only).

Installation Type

Price (inc VAT)

Combi to combi swap


Get a quote

System to combi conversion


Get a quote

New boiler install


Get a quote

Back boiler to a combi


Get a quote

System to system


Get a quote

Frequently Asked Questions

Is Glow-worm a good combi boiler?

Glow-worm combi boilers are generally considered reliable, possessing an A-rating for energy efficiency. They’re suitable for various home sizes, particularly average-sized UK homes with 3-4 bedrooms.

How long does a Glow-worm combi boiler last?

A Glow-worm combi boiler typically has a lifespan of 10-15 years. Regular servicing can help ensure the boiler operates efficiently over its working life.

How efficient is a Glow-worm combi boiler?

Glow-worm combi boilers often achieve an A-rating in energy efficiency, indicating that they convert a high percentage of gas into heat, which can reduce household energy consumption.

Is Glow-worm a budget boiler?

Glow-worm boilers sit at a more affordable price point compared to some other brands, making them a budget-friendly option for many households.

How much does a Glow-worm combi boiler cost?

Prices for Glow-worm combi boilers vary, depending on the model and output. A typical range is from £550 for a basic 24kW model up to around £1,555 for more advanced models.

Can you expect good efficiency from a 24kW Glow-worm combi boiler?

Yes, even a 24kW Glow-worm combi boiler should provide good efficiency levels consistent with the brand’s commitment to energy-saving performance, reflective of its common ErP A-rating.

What is the most economical temperature for my Glow-worm boiler?

The most economical temperature for your Glow-worm boiler may vary based on individual circumstances, but generally setting the thermostat between 18°C and 21°C strikes a balance between comfort and efficiency.

Stephen Day profile photo
Article by
Stephen Day | Co-founder
Gas Safe registered and FGAS certified engineer with over 20 years experience in the heating and cooling industry.