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Last updated: 4th December, 2023


Megaflow Systems: Your Ultimate Guide to Efficient Hot Water Solutions

Megaflow Systems: Your Ultimate Guide to Efficient Hot Water Solutions

Key takeaways

  • Megaflo systems provide a consistent hot water supply and improved heating capabilities
  • These stainless steel unvented cylinders work alongside system boilers and can integrate with renewable energy sources.
  • Factors to consider include cost, performance, efficiency, and comparison with other hot water systems.

Unveiling the Power of Megaflow: Transforming Your Home's Heating and Hot Water Experience

A Megaflo system, often misspelt as "Megaflow system", is a popular choice for those looking to improve their home's hot water and heating capabilities.

This stainless steel unvented cylinder is part of a central heating system. It offers numerous benefits, such as improved efficiency, increased hot water capacity, and seamless integration with renewable energy sources.

In essence, a Megaflo system stores hot water to meet the demands of a household, providing a reliable and continuous flow of hot water when required.

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One of the key aspects of a Megaflo system is its integration with a system boiler, which is responsible for heating the water that fills the unvented cylinder.

The hot water is then distributed throughout a property via a network of pipes, providing central heating and hot water on demand. A significant advantage of this system is its ability to maintain consistent pressure regardless of how many taps or appliances are being used simultaneously, making it an ideal solution for larger households or properties with multiple bathrooms.

When considering a Megaflo system, it's important to weigh the costs, performance, and efficiency, as well as any potential challenges associated with installation and maintenance. Furthermore, it's worth comparing Megaflo to other hot water and heating systems on the market, taking into account factors such as safety features, regulations, and the potential for renewable energy integration.

Megaflow System Components

The Megaflow system is an innovative and efficient solution for providing hot water and central heating in residential properties.

This section will delve into the key components of a Megaflow system, including the unvented cylinder, stainless steel construction, immersion heater, and central heating system.

Unvented Cylinder

An integral part of the Megaflow system is the unvented cylinder. This component stores hot water under pressure, providing a high flow rate of hot water throughout the property. With no need for a cold water storage tank, unvented cylinders save space and help maintain consistent water pressure.

Furthermore, unvented cylinders are insulated, which aids in reducing heat loss and increasing energy efficiency.

Stainless Steel Construction

The Megaflow system's unvented cylinder utilises a robust stainless steel construction. This material choice offers several advantages:

  • Durability: Stainless steel is resistant to corrosion and does not rust, ensuring a long lifespan of the product.

  • Low Maintenance: Due to its corrosion resistance, the stainless steel cylinder requires minimal maintenance and is less likely to suffer from leaks or other issues.

  • Hygienic: Stainless steel is a non-porous material, which means it does not harbour bacteria, making it more hygienic for holding water.

Immersion Heater

The Megaflow system incorporates an immersion heater element within the unvented cylinder. This electric heating element can be used as a backup heating option or in conjunction with the central heating system's primary heat source (e.g., gas or oil boiler).

By providing additional heating capability, the immersion heater ensures a constant supply of hot water even during periods of high demand or if the primary heat source fails.

Central Heating System

The Megaflow system seamlessly integrates with various central heating system types, including gas, oil, and renewable energy-based systems. As the stored hot water in the cylinder is heated primarily by the central heating system's heat source, the Megaflow system provides an energy-efficient, cost-effective, and versatile solution for residential properties.

Having a well-maintained central heating system and keeping it operating efficiently in combination with the Megaflow system's components will yield the best performance and energy savings.

Installation and Maintenance

Installation Process

Installing a Megaflow system involves several steps and can vary based on whether it's a direct or indirect system. Generally, the process begins with choosing the appropriate Megaflow unvented cylinder for your property.

Next, the cylinder is connected to the main water supply and either a gas boiler or an electric immersion heater, depending on the system type. Installation costs can range from £500 to £2,000, while the Megaflow system itself typically costs between £1,000 and £3,500. Keep in mind, this price range may not include VAT or installation fees.

Gas Safe Engineer

Ensuring a proper and safe installation is crucial to the performance and longevity of your Megaflow system. Thus, it's vital to hire a Gas Safe registered engineer. These professionals are certified to work with gas appliances and can ensure all connections are secure, and the system operates efficiently.

Engaging a qualified engineer will not only keep you compliant with regulations but also provide peace of mind knowing your system will function optimally and safely.


Megaflow systems are generally long-lasting, but a comprehensive warranty is essential for added protection. Most manufacturers offer warranties that cover various components, such as the hot water cylinder and the control valves.

The duration of these warranties can vary, so it's important to examine the specifics provided by the manufacturer. Adhering to the recommended maintenance schedule and using a Gas Safe registered engineer for installation can prevent voiding the warranty.

Proper installation and regular maintenance of your Megaflow system contribute to its efficiency and durability. By following these steps and hiring qualified professionals, you can enjoy the full benefits of your Megaflow system with confidence and clarity.

Cost Of A Megaflow System

A Megaflow system involves an unvented boiler and a hot water cylinder. The overall cost of the system depends on factors such as the size of the cylinder and the complexity of the installation process. While it is essential to consider costs, it is equally vital to ensure the system meets your home's requirements.

The price of a Megaflow system boiler paired with an unvented cylinder ranges from £1,000 to £3,500. It is important to ascertain whether VAT and installation fees are included in the quoted price.

The installation work may have an impact on the final cost, so it is wise to account for this aspect when budgeting.

The unvented hot water cylinder installation costs can vary between £500 and £2,000, based on the work necessary for the boiler installation. This variation is due to factors such as accessibility, existing pipework, and additional labour required during the installation process.

In conclusion, when evaluating the cost of a Megaflow system, consider the boiler and unvented cylinder's price, installation fees, VAT, and any additional labour or materials required. By taking a comprehensive approach, homeowners can make an informed decision that suits their budget and meets their home’s needs.

Cost Of Installing A Megaflow System

Installing a Megaflow system can be a significant investment, but one that can provide numerous benefits, such as delivering efficient and consistent hot water supply to your home.

The cost of installing such a system varies depending on factors like the type of property, the complexity of the installation, and the specific components needed in the system.

In general, the price of a Megaflow system boiler with an unvented cylinder ranges from £1,000 to £3,500; however, it's essential to consider whether VAT and installation fees are included in the price.

Additionally, the cost for installing an unvented hot water cylinder falls between £500 and £1,500, depending on the amount of work required for the boiler installation.

When comparing quotes for Megaflow system installation, it's crucial to remember that the price can differ based on the following factors:

  • Size and capacity of the cylinder: The cost often depends on the size and capacity of the unvented cylinder to accommodate the hot water demands of the household. Larger cylinders typically require higher investments.

  • Labour costs: The charges for plumbers and heating engineers can vary depending on their level of experience and the region where the installation is taking place.

  • Extent of modifications: If existing pipework and wiring require significant alterations, the overall price may increase.

  • Additional components: Supplementary parts, such as expansion vessels, thermostatic mixing valves, and pressure reducing valves, contribute to the total cost of the system.

To get an accurate estimation of the cost of installing a Megaflow system, it's advisable to gather multiple quotes from reputable heating engineers. This will enable you to make an informed decision and ensure you're getting good value for your money.

Regardless of the initial investment, a properly installed Megaflow system can lead to long-term savings in energy bills and a considerable improvement in the comfort and convenience of your home's hot water supply.

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Performance and Efficiency

Water Pressure

The Megaflow system boasts a reputation for delivering excellent water pressure. This is due to its unvented design, which ensures consistent high pressure throughout the system. As a result, households benefit from a more satisfactory shower experience and faster-filling baths.

Flow Rate

A significant advantage of the Megaflow system is its impressive flow rate. The unvented stainless steel cylinder enables multiple hot water outlets to operate simultaneously without a noticeable reduction in pressure.

This enhances performance and efficiency for both hot water demand and central heating supply, ultimately providing a comfortable living environment.

Heat Insulation

Megaflow cylinders feature exceptional heat insulation properties, ensuring that the stored hot water remains at a consistent temperature for longer periods. This high-quality heat insulation reduces heat loss and contributes to energy efficiency, making the Megaflow system an eco-friendly and cost-effective choice for homeowners.

In conclusion, the Megaflow system excels in providing high water pressure, excellent flow rate, and efficient heat insulation. These features contribute to an enhanced user experience, increased energy efficiency, and overall improved performance that is highly sought after in modern homes.

Hot Water and Heating Systems

Combi Boilers and System Boilers

Combi boilers and system boilers are two common types of heating devices found in modern homes. These boilers provide central heating and hot water on-demand. Combi boilers heat water directly from the mains, eliminating the need for a storage cylinder, while system boilers store heated water in a separate cylinder, such as the Megaflow Eco Systemfit.

Mains Supply Requirements

Mains supply is essential for both combi boilers and system boilers to function effectively. Some factors that influence boiler efficiency are water pressure, gas supply and electricity availability.

While combi boilers require a minimum water pressure of around 9-12 litres per minute for proper functioning, the Megaflow system demands between 1.5 and 3 bar of pressure.

It's crucial to consider these requirements when installing a new boiler, as consistent mains supply contributes significantly to the boiler's performance and longevity.

Megaflow Eco Systemfit

The Megaflow Eco Systemfit is designed for integration with system boilers. It is a stainless-steel unvented cylinder that efficiently stores hot water for the central heating system. Known for its minimal heat loss figures and quick heat-up and recovery times, the Megaflow Eco Systemfit offers numerous benefits to homeowners seeking reliable heating solutions.

This innovative design incorporates factory-fitted plumbing and wiring, not only saving time during installation but also providing a neater appearance. By combining a Megaflow Eco Systemfit cylinder with a system boiler, homeowners can enjoy consistent hot water supply and a more efficient central heating system.

Safety Features and Regulations

When it comes to the Megaflow system, it is crucial to consider the safety features and regulations implemented. These measures are designed to ensure the utmost protection for users and to maintain the efficient operation of the system. In this section, we will discuss the thermostat, temperature/pressure relief valve (TPRV), and safety guidelines associated with Megaflow systems.


The thermostat plays a key role in maintaining the water temperature within the Megaflow system. By continuously monitoring the water temperature, it can adjust the heating elements as required to maintain optimal and safe temperatures.

The use of a thermostat helps in preventing overheating, which could potentially be harmful to users as well as causing damage to the system.

Furthermore, modern Megaflow systems come with built-in thermostats that offer additional features such as timer settings and precise temperature control. These functionalities contribute to energy-efficient and safe operation.

Temperature/Pressure Relief Valve (TPRV)

The temperature/pressure relief valve (TPRV) is another essential safety feature of the Megaflow system. The purpose of this valve is to relieve any excess pressure that may build up within the system.

The TPRV is designed to open and release water if the pressure or temperature exceeds the specified limits, thereby preventing a potential explosion or damage to the system.

Moreover, it is required by law that the Megaflow system's TPRV is installed and maintained according to the manufacturer's guidelines, ensuring optimum safety for all users.

Safety Guidelines

When using a Megaflow system, it is crucial to comply with the safety guidelines provided by the manufacturer. Strict adherence to these guidelines not only ensures the well-being of users, but it also helps to prolong the life of the system, keeping it running at peak efficiency. Some of the key safety guidelines include:

  • Regularly inspecting the system for any signs of leakage, corrosion, or damage

  • Ensuring that the thermostat and TPRV are functioning correctly and replace any damaged components as necessary

  • Providing adequate ventilation for the system, especially during installation and maintenance

  • Having the system serviced annually by a qualified technician to keep it in optimal working condition

In conclusion, the safety features and regulations of Megaflow systems are crucial to their operation. Familiarising oneself with these inherent safety features, such as the thermostat and TPRV, and diligently following the safety guidelines, can ensure a safe and efficient experience with your Megaflow system.

Renewable Energy Integration

In today's modern world, the integration of renewable energy resources plays a significant role in achieving a sustainable future. Among various types of renewable energy sources, solar power is a crucial contributor to this global transition, having solar panels, solar thermal energy, and solar PV systems as its key components.

Solar Panels

Solar panels, commonly known as photovoltaic (PV) modules, convert sunlight into electricity. By integrating these panels into a larger grid system, renewable energy can be efficiently harnessed and utilised.

Advancements in solar panel technology have made this form of renewable energy more accessible, efficient, and economical than ever before. Commercial and residential applications of solar panel systems include:

  • Rooftop installations for homes

  • Utility-scale installations for businesses

  • Solar farms for communities and power plants

  • Portable solar panels for emergency power or off-grid locations

Integrating solar panels into the grid allows for a more decentralised energy network, enhancing self-sufficiency and resiliency in the face of fluctuating energy prices and resource availability.

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Solar Thermal Energy

Solar thermal energy systems collect and store solar heat to produce hot water, space heating, or steam for industrial processes. This form of renewable energy has numerous applications, from residential to commercial.

The integration of solar thermal energy systems into existing energy networks can contribute to reductions in greenhouse gas emissions and dependence on fossil fuels. Examples of solar thermal energy systems are:

  • Flat-plate collectors

  • Evacuated tube collectors

  • Parabolic trough collectors

  • Concentrating solar power (CSP) systems

With advancements in solar thermal storage technologies, this clean and abundant source of energy can help meet peak demands and provide a consistent, renewable source of heating and cooling.

Solar PV

Solar photovoltaic (PV) systems directly convert sunlight into electricity. The convenience and flexibility of solar PV make it an attractive option for power generation and integration into the grid. With diverse applications ranging from residential homes to large-scale solar power plants, solar PV systems are becoming increasingly popular due to their reliability, affordability, and clean energy production.

Various factors contribute to the efficient integration of solar PV systems into the grid, including:

  • Accurate forecasting of solar energy production

  • Improved energy storage systems to manage fluctuations

  • Flexible grid management to accommodate variable output

  • Interconnecting larger balancing areas to maintain grid stability

In conclusion, the integration of renewable energy systems, particularly solar panels, solar thermal energy, and solar PV, into existing power grids has tremendous potential for fostering a more sustainable, reliable, and environmentally-friendly energy future. By leveraging advancements in technology, infrastructure, and grid management, solar energy can play a significant role in mitigating climate change and enhancing energy independence globally.

Benefits and Challenges

In this section, we will discuss the various aspects of the Megaflow system, including its advantages and potential issues. We will also touch upon the topic of noisy operation, which can be a concern for some users.


Megaflow systems offer several key benefits that make them an appealing choice for many households:

  • Hot water availability: One of the main advantages of a Megaflow system is its ability to store a large volume of hot water, ensuring a reliable supply whenever needed. This is particularly useful for homes with multiple bathrooms.

  • Strong water pressure: As an unvented system, Megaflow mimics the pressure of the mains water supply, providing a consistent and satisfying flow of hot water throughout the house.

  • No need for cold water tanks: Megaflow's unvented design eliminates the requirement for a cold water storage tank, creating more space in your home and reducing the risk of contamination.

  • Compatibility with multiple energy sources: Megaflow cylinders can work with various heat sources, including gas, electricity, and renewable energy, making them suitable for a wide range of households and preferences.

Potential Issues

Despite the many advantages, there are potential issues to consider when installing a Megaflow system:

  • Professional installation required: Due to their complexity, Megaflow systems should be installed by qualified technicians. This can result in higher installation costs compared to traditional systems.

  • Maintenance and water hardness: Megaflow systems may require regular maintenance to prevent issues caused by water hardness and limescale build-up. Investing in a water softener can help extend the system's lifespan and maintain efficiency.

Noisy Operation

Some users have reported experiencing noisy operation with their Megaflow systems, particularly during the reheat process. However, this issue can often be addressed by proper insulation, securing loose components, and maintaining correct water pressure levels.

With careful installation and ongoing maintenance, many households can enjoy the numerous advantages of a Megaflow system without excessive noise or inconvenience.

Comparing Megaflow to Other Systems

Difference Between Vented and Unvented Cylinders

A Megaflow system is an example of an unvented cylinder, which stores hot water under pressure as part of a central heating system. In contrast, a vented cylinder is connected to a cold water storage tank, typically located in the loft, and has a lower pressure. Unvented systems, like Megaflow, offer several advantages:

  • They provide a higher water pressure, which is great for showers.

  • Unvented systems eliminate the need for a cold water storage tank, saving space.

  • The risk of contamination is reduced since the water supply is mains-fed.

However, vented systems can sometimes be easier and less expensive to install and maintain.

Megaflow vs. Combi

Megaflow systems and combi boilers are both popular choices for providing hot water in domestic settings, but they work differently.

  • Megaflow systems use a separate hot water cylinder to store and supply hot water, while combi boilers heat water on-demand and do not require a storage cylinder.

  • Combi boilers are generally more energy-efficient because they only heat the water you use, whilst Megaflow systems store hot water, which can result in some heat loss.

  • Megaflow systems can be better for larger households with simultaneous hot water demands, as they offer a higher flow rate. Combi boilers may struggle to keep up with demand in such situations.

Megaflow vs. Storage Water Heaters

Megaflow systems can be compared to storage water heaters in terms of functionality, but there are some key differences.

  • Megaflow systems are unvented and store hot water under pressure, providing a higher flow rate. Storage water heaters, on the other hand, are typically vented and may have lower water pressure.

  • Megaflow systems rely on a separate boiler for heating, whereas storage water heaters have an integrated heating element.

  • While both systems store hot water, the Megaflow system generally offers better thermal efficiency due to its insulated stainless-steel design. This means that the water in a Megaflow cylinder stays hotter for longer, reducing energy usage.

In summary, Megaflow systems, combi boilers, and storage water heaters each have their unique characteristics and applications. Understanding these differences can help homeowners choose the most suitable option for their hot water needs.

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In this section, we will discuss some popular Megaflow brands, including Heatrae Sadia, Baxi, and Ideal. These brands are renowned for their quality products and reliable performance.

Heatrae Sadia

Heatrae Sadia is a UK-based company and a leading manufacturer of reliable hot water cylinders, including the Megaflow system. The Megaflow cylinder, made of stainless steel, is an essential component of a home's central heating system, providing efficient hot water storage.

Heatrae Sadia not only specialises in cylinders but also produces storage water heaters, radiators, and other heating products.

Some key features of Heatrae Sadia Megaflow cylinders include:

  • High-quality stainless steel construction

  • Excellent insulation for energy efficiency

  • Wide range of sizes and capacities


Baxi, another well-established UK brand, has been in the heating industry for over 150 years. They offer a range of Megaflow-compatible unvented cylinders, designed to work seamlessly with their system boilers. Baxi unvented cylinders provide high-quality performance, ensuring ample hot water supply for households.

The Baxi unvented cylinders have the following notable features:

  • Robust stainless steel design

  • Energy-efficient insulation

  • Variety of sizes and capacities to suit different households


Ideal is a reputable UK brand known for manufacturing top-quality boilers and heating products. Their Megaflow-compatible range of unvented cylinders is designed to work efficiently alongside their system boilers, ensuring a constant supply of hot water for central heating purposes.

Key aspects of Ideal unvented cylinders include:

  • Durable stainless steel build

  • High levels of insulation for energy conservation

  • Wide selection of sizes to cater to diverse household needs

In conclusion, Heatrae Sadia, Baxi, and Ideal are prominent Megaflow system brands, offering exceptional unvented cylinders for domestic central heating systems. These companies provide high-quality, energy-efficient cylinders made from stainless steel to ensure a stable supply of hot water for your home.

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Frequently Asked Questions

What are common problems with Megaflow systems?

Megaflow systems can experience issues such as low water pressure, no hot water, and leaks due to component failure or system design flaws. Regular maintenance can help prevent and address these problems. It's important to consult with a qualified specialist to troubleshoot and rectify any issues.

What is the cost of installing a Megaflow system?

The cost of installing a Megaflow system may vary depending on factors such as the cylinder's size, the installation's complexity, and labour charges. Generally, the cost can range from £1,000 to £2,500. It is advisable to obtain multiple quotations before committing to a specific installer.

Do Megaflow systems use electricity or gas?

Megaflow systems can be powered either by electricity (direct systems) or gas (indirect systems). The choice depends on the user's requirements and the availability of resources. Both options have their advantages and drawbacks, with electricity being more environmentally friendly, and gas generally being more cost-effective.

What are the advantages of a Megaflo cylinder?

A Megaflo cylinder offers several benefits, such as delivering hot water at high pressure to multiple outlets simultaneously, ensuring consistent temperature, and providing rapid water heating without a cold-water storage tank. Additionally, Megaflo cylinders have a lower risk of contamination as they are sealed and unvented.

Is a Megaflo considered a boiler?

A Megaflo system is not a boiler; it is a hot water cylinder designed to work alongside a system boiler. It helps store and distribute hot water throughout the home, ensuring even water pressure and availability of hot water on demand.

Which boilers are compatible with Megaflow systems?

Megaflow systems are compatible with most types of system boilers, given that they can provide a sufficient volume of hot water to meet household demands. However, it is recommended to check if the boiler is hydrogen ready to avoid problems with the upcoming gas boiler ban in 2025. Consulting with a professional installer can help determine the most suitable boiler to pair with a Megaflow cylinder.

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