The high quality, stainless steel uniSTOR cylinder is a hot water storage facility, ideal for domestic properties with a new or existing sealed system or open vent boiler. uniSTOR cylinders are 'unvented' cylinders which means they can operate efficiently under higher pressures, for example in a sealed heating system. Available in a wide range of hot water storage capacities, the uniSTOR is suitable for almost all types of property with a sealed system or open vent boiler. Being suitable in particular for larger properties with multiple bathrooms, heating systems using a cylinder can often provide a higher level of hot water than a combination boiler. Vaillant uniSTOR unvented cylinders can be used when converting from an open vented system (with a cold water tank in the loft) to a sealed system (boiler and cylinder system). Converting to a sealed system can help save space e.g. during loft conversions etc when there is no room for a tank, and in most cases will provide higher water pressure at your taps and shower. By upgrading an old copper cylinder (with insulation jacket) to a new uniSTOR unvented cylinder (as part of a heating system upgrade), you can make your heating system more efficient by reducing your cylinder heat losses significantly, which in turn can help to reduce fuel bills.