Unvented Hot Water

The unvented hot water system pulls water from the mains and then heats it in one of two ways: via direct or indirect heat.

In an indirectly heated water heater, heat is transferred from an external source, generally in the form of a gas boiler or solar panels. The heated water then travels through a copper coil in the hot water cylinder to warm the surrounding water without actually mixing it.

An internal element, such as an immersion heater, is typical in a direct cylinder system. This is required for properties that do not have access to gas, such as off-grid houses.

But why would you choose this system?

In an unvented system, the pressure of hot water flowing from taps and showers is greater. This is because water is taken from the cold-water mains supply rather than a water tank (which is often found in the loft). When several bathrooms may be running hot water from numerous taps at the same time, greater pressure is essential.

The advantage of an unvented hot water system is that a cold-water tank in the property is not necessary, allowing tiny homes to save valuable storage space. Removing the requirement for a tank also eliminates the risk of freezing problems during long cold snaps, such as the Beast from the East in 2018.

Because it is a closed system, there is less risk of contamination and the chance for foreign things to get in and create potential harm.

Finally, homeowners may appreciate an unvented system since noise is reduced. Because the tank isn't filled with cold water, noisy nights caused by vented appliances can be avoided.



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