When an un-vented hot water system is installed both the hot and the cold water supplies within the dwelling, deliver water at the taps or shower outlet at mains water pressure. Cold water from the mains is delivered to the base of the cylinder, the water is heated, then when a tap or shower is turned on the mains water pressure pushes the hot water out.
Advantages of the Unvented Hot Water system
Balanced pressures at hot and cold taps, high performance showering throughout the house, high pressure and hence flow rate of hot water, fast filling baths, potable (drinking) water at all taps, no cold water storage therefore no contamination, quicker to install quiet running and fast recovery (typical 15-20 minutes for 125L), no fear of frozen loft pipes.
