Megaflow System – Cost, Benefits & How It Works

The Megaflow system, also known as a Megaflow boiler system, is a unique unvented hot water cylinder. It’s designed to provide a consistent and robust supply of hot water throughout your home, making it a standout choice for homeowners with high hot water demands.

Unlike traditional vented systems, which typically rely on separate cold-water storage tanks located in lofts, the Megaflow connects directly to the mains water supply. This setup ensures high water pressure and the ability to supply multiple outlets simultaneously, making it an ideal solution for modern households.

Homeowners frequently inquire, “What exactly is a Megaflow system, and is it worth the investment?” The answer varies based on several factors, including the size of your property, your household’s hot water usage, and whether the mains water pressure in your area is sufficient to support this system. To know full details, make sure you read the blog till end!

How Does a Megaflow Work?

The Megaflow system operates by storing water in a well-insulated cylinder, which is heated through either a central heating boiler or an electric immersion heater. This unvented system draws water directly from the mains, offering practical benefits like faster filling for baths and showers, consistent water pressure, and reliable performance for modern heating systems.

Faster filling for baths and showers: With intense mains pressure, you can enjoy quicker filling times for both baths and showers.

Consistent water pressure: The system maintains even water pressure across all taps, showers, and appliances, ensuring an enjoyable and efficient user experience.

Reliable performance: Megaflow systems are particularly advantageous for modern heating systems, which often require a consistent and high-quality hot water supply.

For households with multiple bathrooms or high simultaneous hot water demand, a Megaflow system becomes one of the most practical and beneficial choices available.

Advantages and Disadvantages of a Megaflow System

Advantages

1. High Water Pressure: This system is ideal for power showers and allows for the simultaneous use of multiple outlets without significant drops in water pressure.

2. No Cold-Water Tank Required: By eliminating the need for a cumbersome cold-water tank, Megaflow systems can save crucial loft or storage space while mitigating the risk of freezing during cold weather.

3. Efficient Insulation: The well-insulated cylinder helps keep water hot for extended periods, reducing the frequency of heating cycles and enhancing energy efficiency.

4. Great for Larger Homes: With a consistent and reliable supply of hot water, Megaflow systems are ideally suited for larger homes where high demand is common.

Disadvantages

1. Higher Installation Costs: One of the main drawbacks of a Megaflow system is the higher initial installation cost compared to traditional systems.

2. Dependent on Mains Pressure: If the mains pressure in your area is insufficient, the performance of the Megaflow can be adversely affected. Nevertheless, booster pumps can be installed to help mitigate this issue.

3. Professional Installation Required: To ensure safety and compliance with regulations, a G3-qualified engineer must carry out the installation.

Megaflow System vs. Standard Boiler: Which Should You Choose?

When deciding between a Megaflow system and other heating solutions, the choice largely hinges on factors such as available space, budget constraints, and hot water demand. A Megaflow system is best suited for larger homes equipped with multiple bathrooms where simultaneous hot water usage is a common requirement.

Megaflow System: Best suited for larger homes equipped with multiple bathrooms where simultaneous hot water usage is a common requirement.

Conventional Boiler with Tank: This option is generally more effective for smaller homes or properties with lower hot water demands.

Combi Boiler Alternative: An excellent option for homes with limited space and average hot water usage needs.

If you’re unsure which system best matches your needs, it’s advisable to consult comprehensive guides or seek professional advice on new boiler installations.

How Much Does a Megaflow System Cost?

The cost of a Megaflow system can vary significantly depending on several factors, including the cylinder size, installation specifics, and location. Here’s a general breakdown of costs you can expect in the UK:

 

Item Average Cost (UK)
Megaflow Cylinder (Unvented) £500 – £1,500
Installation (Labour & parts) £700 – £1,500
Total Megaflow Installation £1,200 – £3,000

Although the initial investment may seem high, the long-term efficiency and reliability of Megaflow systems often make them a worthwhile investment.

Disclaimer: Above cost is just an estimate, and original cost may vary depending upon the provider, location and other factors.

Megaflow Cylinder Size Guide

Choosing the appropriate cylinder size is crucial to ensuring an adequate supply of hot water for your household needs. Here’s a helpful guide based on household size:

 

Household Type Recommended Cylinder Size
Small home / 1 Bathroom 125 – 145 Litres
Medium home / 2 Bathrooms 180 – 210 Litres
Large home / 3 Bathrooms 250 – 300 Litres
Very large home / 4+ Bathrooms 300+ Litres

It’s essential to consult with your installer for a thorough assessment, as your actual needs will depend on patterns of hot water usage.

Additional Factors to Consider

When determining if a Megaflow system is suitable for your home, keep in mind the following considerations:

Best Boiler for Megaflow System: A system boiler is typically the most compatible option, although some regular boilers may also work adequately.

Maintenance Needs: Annual servicing is a legal requirement to ensure safety and operational efficiency.

Warranty Coverage: Most Megaflow cylinders come with substantial guarantees, often up to 25 years, providing peace of mind regarding durability and performance longevity.

Water Pressure Check: If your home experiences low mains pressure, it may be worth considering the installation of a booster pump to enhance the system’s performance.

Conclusion

In summary, the Megaflow system is one of the most reliable solutions available for households with significant hot water demands. It is designed to provide high water pressure, make efficient use of space, and support the simultaneous use of multiple water outlets.

While the installation costs range from £1,200 to £3,000, the long lifespan, efficiency, and convenience of a Megaflow system can often justify the upfront expenditure.

FAQs

How long does a Megaflow system last?

A Megaflow cylinder is built for durability and often comes with a 25-year warranty. With proper servicing, it can easily last over two decades. Annual Boiler service is important to maintain efficiency and comply with safety standards. For added protection, you may also consider a boiler cover that includes hot water systems.

Does a Megaflow system work with a combi boiler?

No, a Megaflow system is not designed to work with a combi boiler, since combis don’t require separate hot water storage. Instead, a system boiler or a regular boiler is the best boiler for a Megaflow system.

How do I know if my mains water pressure is good enough for a Megaflow?

The Megaflow relies entirely on mains water pressure. Ideally, your home should have at least 1.5 bar pressure for optimal performance. If your pressure is lower, you may notice issues like a boiler losing pressure. In such cases, you can read our guide on how to increase boiler pressure.

What is a tundish and why is it important in a Megaflow system?

A tundish is a small safety device fitted with unvented cylinders, including Megaflow systems. It provides a visible route for water discharge if pressure inside the cylinder gets too high. This is a key safety feature and should never be overlooked.

Is a Megaflow system energy efficient?

Yes, Megaflow systems are highly efficient thanks to their insulated cylinders that keep water hot for long periods. This reduces the need for frequent reheating. However, efficiency also depends on the boiler type paired with the Megaflow, a modern A-rated system boiler can maximise savings on your energy bills.

Can I upgrade from a vented system to a Megaflow?

Yes, many homeowners replace their older vented systems with a Megaflow to enjoy higher pressure and better performance. However, this often involves additional pipework and potentially higher installation costs. For accurate pricing, it’s best to get a quote for both the cylinder and megaflow system installation cost.

Posted by: Aliyan Nawab 08 October 2025