MegafloHot Water Cylinders

An indirect Megaflo is heated via a coil connected to your boiler, making it the right choice if you already have (or are fitting) a gas or oil boiler. A direct Megaflo has its own electric immersion elements and suits properties without a boiler, such as those heated by electric storage or air source systems with no coil provision. If in doubt, match the cylinder type to your existing or planned heat source rather than the other way round.

No — that's the main advantage of a Megaflo over a traditional gravity-fed cylinder. Megaflo cylinders are pressurised directly from the mains, so there's no need for a cold water storage tank or header tank in the loft. This frees up loft space and simplifies pipework, though it does mean the cylinder relies on adequate incoming mains pressure and flow to perform properly.

Sizing depends on the number of bathrooms, occupants and simultaneous demand rather than property size alone — as a rough guide, a two-bathroom household typically needs 150-210 litres, while larger homes with three or more bathrooms often need 250 litres or above. Because Megaflo cylinders maintain pressure across multiple outlets, it's worth sizing generously if you regularly run showers and taps at the same time. Our team can help you match litre capacity to bathroom count and usage pattern if you're unsure.

Megaflo cylinders can generally be sited in an airing cupboard, utility room or garage, as they don't need loft height or gravity feed like older systems. However, they do need to be installed upright on a suitable floor able to bear their weight when full, with sufficient clearance for servicing and pipework connections. A slimline Megaflo is worth considering where cupboard or floor space is restricted.

Yes — unvented cylinders like Megaflo fall under Building Regulations Part G3 in England and Wales, and installation must be carried out or signed off by a competent, G3-qualified engineer. This covers the pressure and temperature relief valves, discharge pipework and expansion arrangements that are essential for safe operation. Always check your installer holds the relevant unvented hot water qualification before work begins.

Megaflo cylinders rely on incoming mains pressure and flow rate to deliver strong performance at multiple outlets simultaneously, so a weak or inconsistent mains supply will limit results regardless of cylinder size. It's worth having your installer check static pressure and flow rate before specifying a cylinder, particularly in rural properties or those on shared supplies. Where mains pressure is genuinely low, a booster pump may be needed alongside the cylinder to achieve the performance you're expecting.