Introduction to hot water cylinders

Hot water cylinders store and keep your water warm until you need it. Unless, you have a combi boiler, which heats water directly from the mains, then you will need a hot water cylinder within your heating system. This article will explain the different types of hot water cylinders that can help to heat your home.

Unvented systems do not need a cold water tank, as the system gets supplied directly from the mains. As they operate at mains pressure, they offer good flow rates, providing your shower and bath with a high level of performance.

Without the requirement for a cold water tank, means you have more space available in the loft. It also removes the potential that the water freezes over during cold winter periods. In addition, as you are not relying on gravity to move the hot water around the home, an unvented cylinder can be placed anywhere in your property.

Unlike, an unvented system, open vented cylinders are supplied water from storage tanks, usually found in the loft. This system relies on gravity to drive the hot water around the home to your taps. A vent pipe is used to connect the vented hot water cylinder and the cold water in the header tank.

The hot water pressure is determined by the height of the water tank above the tap or shower feed. This means that the water pressure might be lower, upstairs than it is downstairs. As a result, homeowners with vented hot water tanks, quite often make use of electric pumps to drive the hot water to the shower at an increased pressure.

Vented hot water cylinders tend to be a cheaper option than an unvented cylinder, as they are less complicated, meaning they are much simpler to maintain and install.

In a direct cylinder system, the hot water is heated directly by an immersion heater. Although, this type of cylinder is generally fitted with two different immersion heaters, one for peak electricity and the other for off-peak electricity. If this is the case, you need to make sure that the heaters are set to function at the right time, to ensure that you are getting good value for money, when considering the rate for hot water.

Most hot water cylinders are heated through an external source, like a gas boiler. In this instance, the water is heated, before travelling through a copper coil in the hot water cylinder. The heat is then transferred from the external heat source to the water inside the cylinder.

Indirect cylinders tend to be fitted with a direct backup, usually an immersion heater, meaning, even if the boiler is broken, you can still produce hot water when you need it.

These cylinders are designed specifically for solar heating installations. When a mixture of water and Glycol liquid passes through solar panels, heat is transferred to the stored water through an internal coil. After the hot water is produced, it is rerouted through the solar panels to be reheated. This system also comes with an additional coil, allowing heat to be taken from an alternative source if necessary.