UNVENTED HOT WATER CYLINDERS
Unvented hot water cylinders were only made legal in the UK in 1986, but have since grown rapidly in popularity. In an unvented system there is no cold water tank – instead the sealed hot water cylinder is fed directly by the cold water mains.
BENEFITS OF UNVENTED HOT WATER CYLINDERS
Since they are operating at mains pressure, they offer much better flow rates, meaning your shower and bath performance should be higher.
The other major benefit is that you don’t need to maintain a cold water tank in the loft (which vented systems require). This is good news since not only does it free up space, it also removes the potential freezing issue during our long cold winter periods.
In addition, since you aren’t relying on gravity to move the hot water around the home, the unvented cylinder can be located pretty much anywhere in your property.
Other advantages of installing an unvented system include reduced noise in the system since there is no cold water filling of the water storage cistern, and since there is no water storage cistern and the system is essentially sealed, the cold water is not at risk from contamination.