

A Megaflow system, also known as a Megaflo unvented system, is a high-performance water storage cylinder that integrates seamlessly into a central heating system. This unvented hot water cylinder offers numerous advantages over traditional vented systems, providing high-pressure hot water and efficient performance.
Megaflow systems, with their reliability and cutting-edge technology, are a significant stride towards sustainable living. They align perfectly with our mission to foster the transition to more eco-friendly and energy-efficient households.
This guide is a deep dive into the intricacies of the Megaflow system, covering its benefits, installation requirements, and maintenance tips. Whether you're a homeowner considering an upgrade or a professional installer, this comprehensive guide is for you. It will equip you with valuable insights into the Megaflow system.
A Megaflow system comprises a high-quality stainless steel unvented hot water cylinder designed to store and deliver pressurised hot water. Unlike traditional vented systems, Megaflow cylinders connect directly to the mains water supply, eliminating the need for a cold water storage tank in the loft.
This design ensures high water pressure and a consistent flow of hot water throughout the home.
It is ideal for properties with multiple bathrooms or high hot water demand.
Manufacturers like Heatrae Sadia, a leading British company specialising in hot water solutions, Megaflo cylinders have earned a reputation for reliability and performance. These systems cater to modern households with high hot water demands. They are particularly suitable for homes with multiple bathrooms or those requiring simultaneous hot water usage at various outlets.
| Specification | Value |
|---|---|
| Material | Duplex Stainless Steel |
| Insulation Thickness | 60mm |
| Maximum Operating Pressure | 3.5 bar |
| Minimum Recommended Pressure | 1.5 bar |
| Flow Rate | Up to 72 litres per minute |
| Warranty | 25 years |
| Installation Cost | £2,000 - £3,000 |
Megaflow cylinders operate on a simple yet effective principle. They provide a consistent supply of high-pressure hot water throughout a property.
3. Pressure management: As the water heats up, it expands within the sealed cylinder. To manage this increased pressure:
4. Hot water delivery: Hot water exits the cylinder at the main pressure when taps or showers are turned on. This provides powerful showers and fast-filling baths without the need for additional pumps.
5. Continuous supply: The large storage capacity of Megaflow cylinders (typically ranging from 100 to 300 litres) ensures a plentiful hot water supply. As people use hot water, cold water enters the bottom of the cylinder to replace it. The system then heats this cold water to maintain the supply.
6. Temperature control: A thermostat monitors the water temperature, activating the heating source when it drops below the set level (usually around 60°C).
7. Safety features: Megaflow systems include several safety mechanisms, such as temperature and pressure relief valves, to prevent overheating or excessive pressure buildup.
The mains pressure delivery also eliminates the need for gravity-fed systems, allowing greater flexibility in bathroom and kitchen layouts.
| Feature | Value |
|---|---|
| Energy Rating | A |
| Recovery Rate | 0.7 kW/hr |
| Heat Loss | 1.39 kWh/24hr |
| Annual Energy Consumption | 1277 kWh/annum |
| Water Heating Efficiency | 93% |
The Megaflow system offers several key features that make it an attractive choice for many households.
The cost of installing a Megaflow system can vary depending on the cylinder size and the installation's complexity. On average, homeowners expect to pay between £2,000 and £3,000 for a typical installation.
It's vital to check if this includes VAT and installation fees. Installing an unvented hot water cylinder alone can range from £500 to £1,500, influenced by the workload involved with the boiler setup.
While the initial investment may be higher than traditional systems, the long-term benefits often justify the cost. These benefits include improved efficiency and performance. Here is a detailed breakdown of cost implications.
| Property Size | Cylinder Size | Estimated Cost Range | Cost Factors |
|---|---|---|---|
| Small (1-2 bedrooms) | 150-180 liters | £1,500 - £2,500 | - Straightforward installations in inaccessible locations - Higher costs if significant pipework modifications are needed |
| Medium (3-4 bedrooms) | 210-250 liters | £2,000 - £3,500 | - Typical installations - Higher costs of relocating the cylinder or extensive plumbing work are required |
| Large (5+ bedrooms) | 300+ litres | £2,500 - £4,500+ | - Larger cylinder size - Potentially more complex installations - May require upgrades to existing pipework |
For the most accurate cost estimate, it is recommended to get quotes from multiple qualified installers.
These installers can assess the specific requirements of your property.
Megaflow cylinders are available in various sizes to suit different household needs. The following table provides an overview of common Megaflow cylinder specifications:
| Capacity (litres) | Height (mm) | Diameter (mm) | Weight (empty) kg | Weight (total) kg | Heat Loss (kWh/24h) | Recovery Time (mins) |
|---|---|---|---|---|---|---|
| 125 | 1102 | 579 | 39 | 179 | 1.05 | 18.3 |
| 145 | 1229 | 579 | 44 | 199 | 1.10 | 18.7 |
| 170 | 1384 | 579 | 48 | 230 | 1.15 | 24.3 |
| 210 | 1486 | 579 | 51 | 250 | 1.20 | 24.3 |
| 250 | 1738 | 579 | 57 | 293 | 1.25 | 23.9 |
| 300 | 2053 | 579 | 65 | 348 | 1.30 | 24.5 |
Note: Heat-up times are approximate and based on a 45°C temperature rise using a 3kW immersion heater.
The total cost of a Megaflow system can range from £1,000 to £4,000, depending on the property's size, the installation's complexity, and the specific components required. Here is a summary table:
| Property Size | Cylinder Size | Cylinder Cost | Installation Cost | Total Cost |
|---|---|---|---|---|
| Small (1-2 bedrooms) | 70-150 liters | £500-£1,000 | £500-£1,000 | £1,000-£2,000 |
| Medium (3-4 bedrooms) | 150-250 liters | £800-£1,500 | £1,000-£1,500 | £1,800-£3,000 |
| Large (5+ bedrooms) | 250-300 liters | £1,200-£2,000 | £1,500-£2,000 | £2,700-£4,000 |
While initial costs may be higher than traditional vented systems, long-term benefits often justify the investment. Improved efficiency, reduced maintenance requirements, and enhanced comfort contribute to the overall value proposition of Megaflow systems.
One of the standout benefits of the Megaflow system is its ability to provide high water pressure. This is particularly beneficial for homes with multiple bathrooms, as it ensures a consistent flow of hot water even when several outlets are in use simultaneously. The design of the unvented cylinder plays a pivotal role in achieving this, ensuring that users experience consistent high pressure throughout the property.
Eliminating a cold water storage tank frees up space, allowing for more flexible installation options. This makes the Megaflow system an excellent choice for homes with limited space.
The Megaflow system can be integrated with renewable energy sources such as solar panels, providing an eco-friendly solution for your hot water needs. For instance, the Megaflo Eco Solar PV Ready system utilises surplus solar electricity to heat water, enhancing energy efficiency and reducing utility costs. This system's ability to work with existing or new PV arrays makes it an adaptable solution for eco-conscious homeowners.
This compatibility reduces energy bills and contributes to a greener environment.
Installing a Megaflow system requires professional expertise due to its complexity and the need to comply with building regulations. Essential installation requirements include:
Regular maintenance is crucial to ensure the longevity and efficiency of the Megaflow system. Here are some essential maintenance tips to keep your system running smoothly:
These maintenance tips can help ensure your Megaflow system operates efficiently and safely.
Additionally, scheduling regular professional servicing will contribute to your system's longevity for years.
Remember, while homeowners can perform some basic maintenance, it's always best to rely on qualified technicians for more complex tasks and annual servicing.
Determining whether a Megaflow system suits your home involves weighing its advantages and disadvantages. The following table summarises the key pros and cons to help you make an informed decision.
| Pros | Cons |
|---|---|
| High Water Pressure: Megaflow systems provide high-pressure hot water (up to 25 litres/minute) directly from the mains, ensuring powerful showers and quick-filling baths. | Space Requirements: Although they eliminate the need for a cold water tank, Megaflow cylinders are bulky and require significant storage space. |
| Consistent Performance: Capable of maintaining water pressure even when multiple outlets are in use simultaneously, making them ideal for larger households. | Heavy and Bulky: The cylinders are heavy and can be cumbersome to install, requiring adequate structural support. |
| No Cold Water Tank Needed: Frees up loft space and reduces the risk of water contamination from stagnant water. | Professional Installation Required: Due to their complexity, Megaflow systems must be installed by qualified technicians, which can increase installation costs. |
| Compatibility with Renewable Energy: Can be integrated with solar panels and other renewable energy sources, reducing fuel costs and environmental impact. | Maintenance and Water Hardness: Regular maintenance is necessary to prevent issues caused by water hardness and limescale build-up. A water softener may be required in hard water areas. |
| Safety Features: Equipped with temperature and pressure relief valves, ensuring safe operation. | Potential Noise: High water velocity can cause noise during operation, which may be bothersome in some homes. |
| Energy Efficiency: Well-insulated design minimises heat loss, improving energy efficiency. | Dependence on Mains Pressure: The system's performance will be affected if the mains water pressure is low. A flow rate test is recommended before installation. Requires minimum 1.5 bar mains pressure to function optimally |
| Backup Heating: In case of boiler failure, the system can use an immersion heater or solar PV for hot water. | Recovery Time: It takes about 45 minutes to reheat water after the stored hot water is depleted. |
Is it suitable for your home? Consider:
Consult a qualified heating engineer to assess your situation and home layout before deciding.
When evaluating heating systems, comparing the Megaflow system with other options like combi boilers and vented cylinders is crucial. Each system offers unique benefits suited to different home environments.
When considering a new hot water system, homeowners often debate between Megaflow systems and combi boilers. However, both options have their merits, and ultimately, the choice depends on individual circumstances.
| Feature | Megaflow System | Combi Boiler |
|---|---|---|
| Water Pressure | High water pressure, ideal for homes with multiple bathrooms. | It relies on mains pressure, which can drop if multiple outlets are used simultaneously. |
| Hot Water Availability | Stores ample hot water, ensuring a constant supply during peak times. | Heats water on demand, which can be limiting during peak usage times. |
| Space Requirements | Requires more space due to the separate hot water cylinder. | Compact and space-efficient, combining heating and hot water in a single unit. |
| Energy Efficiency | It can be highly efficient, especially with renewable energy sources, but may have higher standby heat losses. | Generally more energy-efficient as it heats water on demand, reducing energy waste. |
| Installation and Maintenance | More complex and costly installation; straightforward maintenance but may require piping upgrades. | More accessible and less disruptive installation; simpler and less expensive maintenance. |
| Suitability | It is best for larger homes with multiple bathrooms and high hot water demand. | It is ideal for smaller homes or apartments with moderately hot water needs. |
Choosing between a vented cylinder and a Megaflow system depends on various factors, including the size of your home, the number of bathrooms, available space, and your budget.
| Feature | Megaflow Systems | Vented Cylinders |
|---|---|---|
| Water Pressure | Provides consistent mains pressure, ensuring strong water flow throughout the house. | It relies on gravity, leading to variable pressure, often lower on upper floors. |
| Installation Location | Flexible; can be installed in lofts, airing cupboards, or other convenient locations. | It requires a loft tank, limits installation options, and requires significant space. |
| Space Requirements | There is no need for a cold-water storage tank, saving space. | It requires a cold-water storage tank, which takes up loft space. |
| Cost | Higher installation and maintenance costs due to complexity. | It is generally cheaper to install and maintain due to its more straightforward design. |
| Maintenance | Requires regular professional maintenance to ensure safety and efficiency. | Minimal maintenance needed, simpler system. |
| Water Supply Security | Dependent on mains water supply; hot water if supply is not interrupted. | The loft tank provides a backup water supply during mains interruptions. |
| Performance in Large Homes | It is ideal for homes with multiple bathrooms due to strong and consistent pressure. | Additional pumps may be required to maintain pressure in homes with multiple bathrooms. |
These brands showcase a commitment to quality and innovation, each bringing unique features to the table that cater to different user needs and preferences in home heating solutions.
Heatrae Sadia originally manufactured the Megaflo brand, but other companies now produce similar high-quality unvented cylinders that people often compare to or refer to as "Megaflow" systems. However, brands like Baxi, Gledhill, Vaillant, Telford, and Viessmann offer competitive alternatives with varying capacities and price points.
| Brand | Feature | Cylinder Capacity (in litres) | Price Range (in £) |
|---|---|---|---|
| Heatrae Sadia Megaflo Eco | Heatrae Sadia is a leading manufacturer of unvented hot water cylinders known for their reliability and performance. Their Megaflo Eco range is trendy. | 70 - 300 | £625 - £2,500 |
| Heatrae Sadia Megaflo Eco Plus | 250 - 1,100 | £800 - £2,000+ | |
| Baxi | Baxi offers a range of Megaflow systems that are compact and efficient, making them ideal for homes with limited space. | 125 - 300 | £600 - £1,800 |
| Telford | Telford's Tempest range is made from high-quality stainless steel, offering excellent corrosion resistance and various capacities. | 90 - 500 | £500 - £1,800 |
| Gledhill | Gledhill's StainlessLite Plus range is known for its durability and energy efficiency, offering a variety of capacities to suit different needs. | 90 - 300 | £600 - £2,000 |
| Vaillant | Vaillant's uniSTOR range is designed for high performance and energy efficiency, focusing on ease of installation and maintenance. | 150 - 500 | £700 - £2,200 |
| Viessmann | Viessmann's Vitocell DHW cylinders have high energy efficiency, with all models achieving at least energy efficiency class B as standard and selected models reaching class A or A+, resulting in reduced standby losses of up to 45% compared to efficiency B and C class cylinders. | 160 - 500 | £700 - £2,500 |
Please note: The approximate price ranges can vary based on factors like specific models, capacity, and retailers. Moreover, prices and available models may change over time, so it's always best to check with current suppliers for the most up-to-date information.
Megaflow systems have gained popularity recently due to their significant contributions to energy efficiency and reduced environmental impact. Let's explore these aspects in more detail:
Superior Insulation: Designers use high-quality insulation materials to minimise heat loss in Megaflow cylinders. This superior insulation helps maintain water temperature for extended periods, reducing the need for frequent reheating. The cylinders typically use polyurethane foam insulation, which has excellent thermal properties and can retain heat for up to 24 hours. This results in less energy consumption and lower utility bills for homeowners.
Compatibility with Renewable Energy Sources: One of the key advantages of Megaflow systems is their compatibility with various renewable energy sources. Moreover, this flexibility allows homeowners to integrate eco-friendly heating options into their homes, such as:
By supporting these renewable energy sources, Megaflow systems contribute to reducing reliance on fossil fuels and lowering carbon emissions.
Efficient Heat Transfer Design: Engineers design Megaflow cylinders for optimal heat transfer, maximising energy utilisation. The design typically includes:
Reduced Water Wastage: Megaflow systems maintain consistent pressure and flow rates throughout the property, which leads to reduced water wastage in several ways:
Integration with Smart Home Systems: You can integrate many modern Megaflow systems with smart home technology, allowing for:
Long-term Environmental Benefits: The durability and efficiency of Megaflow systems contribute to long-term environmental benefits:
Carbon Footprint Reduction: When combined with renewable energy sources, megaflow systems can significantly reduce a property's carbon footprint. For example:
Megaflow systems offer a modern, efficient solution for hot water delivery in homes and commercial buildings. With their high-pressure performance, space-saving design, and compatibility with various heat sources, these unvented cylinders provide numerous advantages over traditional vented systems.
Although installation requires careful consideration and professional expertise, the long-term benefits of Megaflow systems often outweigh the initial investment. For households with high hot water demands or those seeking to improve their property's energy efficiency, Megaflow cylinders present an attractive option.
As with any significant home improvement, thorough research and consultation with qualified professionals ensure the best decision for individual circumstances. Property owners can make informed choices about their hot water solutions by understanding the features, benefits, and considerations associated with Megaflow systems.
This knowledge allows them to select the best option for their specific needs. Choosing the right system can enhance comfort, efficiency, and sustainability in their homes.
It is recommended that Megaflow systems be kept on continuously. The tanks are highly insulated, which means they retain heat very well. Once the water reaches the desired temperature, the system will automatically shut off and only reactivate to maintain the temperature when necessary.
The life expectancy of a Megaflow tank typically ranges from 20 to 25 years when properly maintained. However, this can vary depending on factors such as water quality, usage patterns, and adherence to maintenance schedules. Regular servicing and prompt attention to any issues can help extend the lifespan of your Megaflow system.
To maximise the efficiency of your Megaflow system:
A Megaflo system typically operates at a pressure of 3 bar, regulated by the Cold Water Combination Valve. This valve can handle a maximum mains supply pressure of up to 16 bar (1.6 MPa).

Inemesit is a seasoned content writer with 9 years of experience in B2B and B2C. Her expertise in sustainability and green technologies guides readers towards eco-friendly choices, significantly contributing to the field of renewable energy and environmental sustainability.
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