Unvented Cylinders - FAQs, Benefits & Installation (Pulborough)

FAQs on unvented cylinders

If your hot-water pressure is poor or you want a compact, flexible cylinder that works with modern heating systems, an unvented cylinder could be the right choice. This guide answers the most common FAQs on unvented hot water cylinders, explains how they differ from traditional vented systems and highlights what you need to know about installation, safety and maintenance.

What is an unvented hot water cylinder?

An unvented hot water cylinder is a pressurised system that helps deliver hot water at mains pressure. Because it operates off the mains supply, it is a great option for homeowners with weak-performing showers and baths, where the water pressure for hot water is considerably poor. Unvented cylinders can be used without the need for a cold water storage tank, making them a great option for homeowners that are pushed for space.

The water inside the cylinder can be heated directly via an immersion heater, or indirectly via the central heating system or other renewable technologies like solar thermal or heat pumps, making them a great option for almost any home.

Unvented vs vented cylinders: what’s the difference?

Unlike an unvented hot water cylinder, a vented hot water cylinder takes the more traditional approach whereby it needs a cold water storage tank (usually in the loft) in order to work. The water is then drained down into the hot water cylinder below and heated via an immersion heater or indirectly via the central heating system.

The biggest issue with vented cylinders is that they don’t always deliver a higher pressure of water, because the system relies on the cold water tank above acting as an expansion tank as well as a store. There is one benefit to a vented cylinder though: they are typically cheaper and require less maintenance due to their simpler nature.

Pros and cons of unvented and vented systems

• Unvented cylinder pros:
  • No loss in mains water pressure for better showers and simultaneous use
  • Takes up less space than vented systems due to not needing a cold water feed
  • No chance of freezing or water contamination
  • Works with immersion heaters, boilers and renewable heat sources
• Unvented cylinder cons:
  • Requires more maintenance than a vented system
  • Can have compatibility issues with selected mixer and power showers
• Vented cylinder pros:
  • Cold-water tank acts as a backup water supply should the mains fail
  • Low maintenance and easy to maintain
  • Lower installation cost
• Vented cylinder cons:
  • Depending on the setup, can provide lower than mains pressure
  • Takes up more space and requires a loft for the cold water feed

Who is qualified to install an unvented hot water cylinder?

All unvented hot water cylinders must be installed by an engineer with a G3 Unvented Qualification. It is vital that the cylinder is installed correctly with all of the essential safety controls.

Where can an unvented cylinder be located?

Because unvented hot water cylinders are pressurised systems, they can be installed in almost any location, making them ideal for homeowners that are tight for space. You can install them in a loft, garage, downstairs — wherever suits — although you will have to accommodate a safety discharge pipe.

How often should an unvented cylinder be serviced?

We’d recommend servicing your unvented hot water cylinder at least once a year, alongside booking your boiler in for a boiler service. Doing so can help you keep your central heating system in great shape for years to come. You can also enquire about our unvented cylinder installation and servicing options.

Would you like to install an unvented hot water cylinder in Pulborough?

Our engineers are G3 qualified and trained to install unvented hot water cylinders. If you would like to get in touch, please give us a call on 01903 740538 or 07871 725133, or send us a message using our contact form. In addition to Pulborough, we also cover Storrington, West Chiltington, Petworth, Fittleworth, Ashington, Billingshurst, Coldwaltham, Findon, Steyning, Horsham and all surrounding areas. You can also read more on our unvented cylinder installation page. We’ll look forward to hearing from you soon.