What is a vented hot water tank?

Vented hot water tanks, also known as gravity-fed, receive their water supply from a header tank (usually in the loft of a house). The height of the header tank determines the pressure of the water delivered to the taps meaning the pressure can sometimes be worse in the upper floors of a house. Installing a water pump to drive water from the tank to the taps will increase the water pressure.

In residential areas with low water pressure a vented system may be the most suitable.

What is an unvented hot water tank?

Unvented hot water tanks, also known as a pressurised system, receive their water supply directly from the cold mains feed, ensuring there is always a strong flow of hot water delivered to the taps without the need for a header tank to drive the water pressure. These systems are supplied with safety equipment and must be installed by a qualified heating engineer who can install to G3 regulations.

Direct Electricity

A direct tank will heat the water directly using an electric immersion element located physically within the tank. This will heat the water in the same way a kettle electrically heats the water.

All Mixergy tanks are built with two immersion elements. One immersion is positioned near the top of the tank to facilitate Mixergy’s ‘top-up’ technology, and a second immersion towards the bottom of the tank is available as a back-up heat source.

Renewables: Solar PV

If you have solar panels installed on your roof, you can self-generate electricity to heat your water. The photovoltaic (PV) panels absorb the energy from sunlight and convert it into electrical power. You’ll need a PV diverter in order to detect that the house is generating more power than it is using, to divert the surplus PV into your hot water tank.

This will require a PV immersion element to be fitted within the tank. This can be fitted at the time the tank is built, or later retrofitted by a qualified installer.

Indirect Gas, oil, biomass burner

An indirect tank will use an external energy source, such as a system gas boiler or oil burner which is fed into the cylinder via a coil which indirectly heats the hot water within the tank.

Mixergy tanks can fitted with a twin coil arrangement to allow you to heat your water from two indirect heat sources. All indirect Mixergy tanks are fitted with two electric immersion elements, allowing you to heat both direct and indirectly if you wish, or to act as a back-up heat source if your indirect source stopped working.

Renewables: Solar thermal

Solar thermal panels harness the suns energy to heat the liquid (water and glycol) inside the collector panels before it is fed through a heat exchanger coil to indirectly heat the water within the tank.

If you are using solar thermal as your second indirect heat source then you will require your Mixergy tank to be configured with a twin coil.