Unvented hot water cylinders

There are typically two types of hot water cylinders found in homes today.

  • Vented Hot water cylinders

  • Unvented hot water cylinders

Vented Hot Water Cylinders

the traditional hot water tank

Vented cylinders are the more traditional and still the most common type of hot water system found in homes in the UK. These copper tanks are fed by cold water and are connected by a vent pipe to a header tank, which is usually located within the loft space in most properties.

In these systems the hot water pressure is determined by the pressure created by gravity and the height of the water tank above the tap or shower feed. Whilst the pressure on the ground floor of the home may be good, it can also mean the upper floors suffer from a lower pressure. As a result, many homes with vented hot water tanks rely on electric pumps to pressurise the hot water for showers.

Unvented Hot Water Cylinders

the modern hot water tank

An unvented hot water cylinder is a pressurised system fed directly from the cold mains water supply, which is designed to provide hot water at mains pressure to all outlets within the home.  These tanks are commonly used to improve shower water pressure in homes with more than one bathroom.

As the tank is fed by the mains water supply it means that there is no need for a cold-water tank and the associated pipework, or a pump to maintain the pressure, so it means there is a reduction in system noise, as there are no cistern or pump noises. It also means that the cylinder can be located almost anywhere in your property, so it is ideal if you are limited for space as it has the added advantage of freeing-up space in the loft whilst providing a better flow rate and water pressure for your shower or bath. This improved water pressure is a hugely beneficial, particularly for homes with more than one bathroom.

Unvented cylinders usually include safety and performance features such as pressure relief valves and temperature controls to keep maintain efficiency. They also benefit from minimal heat loss, fast reheat times and are available in modern designs to suit most homes.

Advantages of installing an unvented hot water cylinder:

  • Better flow rate / water pressure

  • Tanks can be sited anywhere

  • Reduced system noise (no need for pumps or cisterns)

  • No need for a cold-water tank

  • Ideal for homes with more than one bathroom

  • Reduced risk of water contamination as the unit is sealed

Indirect Systems

The majority of hot water cylinders are heated by an external source; the boiler, if not solar thermal. In this system setup the hot water is heated and passes through the copper coil in the hot water cylinder, transferring the heat from the source to the water in the tank.

Direct Systems

In this system setup there is an element inside the tank; such as an immersion heater. Although these systems are more expensive to run, they are often advantageous as for flats, particularly where there is no gas connection and the tank can therefore be powered by electric. In this situation, there are usually two immersion heaters fitted; one for peak electricity and one for off -peak, so you will need to ensure the immersion timers operate to minimise your utility bills.

Hot Water Cylinder Installations

by our Gas Safe heating engineers

We can install a hot water cylinder to modify and improve the hot water pressure of the showers and baths in your home, or as part of a complete central heating system installation. However, it will depend on which boiler you have installed and its compatibility with a hot water cylinder. Unvented cylinders can be installed in a cupboard, a loft, utility room, garage or wherever the most suitable space is in your home.

Most commonly we install Heatre Sadia Megaflo cylinders, Worcester Bosch Greenstore 180 litre cylinders or Joule 300 litre tanks depending on the property and usage requirements. Our Gas Safe registered heating engineers are able to offer professional advice on which cylinder is best suited for your heating system and household usage requirements.

Contact Us

Please contact us for more information about hot water cylinder installations, or to arrange a visit by one our expert Gas Safe Registered heating engineers to assess your home heating requirements and provide an obligation free quotation.

Call: 020 8367 9969

Email: office@pettiferplumbing.co.uk