Unvented cylinders are mains pressure hot water storage systems that provide a highly efficient way of storing and distributing domestic hot water at mains pressure throughout your home. These cylinders are not open to the atmosphere, unlike open vented cylinders which are open to the atmosphere via the cylinder's vent pipe and the cylinder's cold feed pipe from the cold water storage cistern/tank. These mains pressure cylinders provide quicker heat recovery than the low pressure open vented cylinder, i.e, it takes less time to heat up.

Because water is supplied from the mains supply and not from a cold water storage cistern/tank, the flow rate and water pressure from a unvented cylinder at the outlets is much greater than from the storage fed open vented cylinder.

Advantages of Unvented Cylinder Systems

There are a number of advantages with using an unvented hot water cylinder. For example:

• High water pressure; great for showers so no need for booster pumps
• Balanced water pressure at hot and cold taps
• Balanced shower pressure allowing for safer temperature control
• No cold water storage cistern/tank enabling loft conversion
• Improved cylinder location flexibility due to mains water pressure
• Quicker to install than an open vented cylinder and its associated fittings

Unvented Cylinder System Photos