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Unvented Hot Water Cylinders

Unvented Cylinders

What are they?

  •  An unvented cylinder is a pressurised cylinder which is fed directly from the incoming water mains and will supply your house with hot water.

What is the difference between a vented and an unvented cylinder?

The difference between these two cylinders are that a vented cylinder is fed from a storage water tank normally located in your loft and relies on gravity to push the water through your taps.

An unvented cylinder is fed directly off the incoming main so you achieve mains pressure at all your taps/showers (hot and cold) without the need of a pump and removing the stored water from your loft space!

Are they safe?

This is a common question we are asked by our customers and our answer is yes. As long as they are installed by a qualified engineer. If they are installed incorrectly then yes they have the potential to become unsafe but that is the same with many products across the plumbing industry. Our engineers are fullly qualified and all work undertaken by Southern Energy Solutions comes with a 12 month warranty. 

What are the advantages of having a unvented cylinder?

 There are many advantages of installing an unvented cylinder in your home/work place.

  • They are compact and don’t require a lot of space to install.
  • No need for storage tanks in your loft.
  • You achieve mains pressure on your hot and cold taps (giving you nice powerful showers).
  • Can be heated via many heat sources e.g. solar, heat pumps. Or just good old fashioned electric off the immersion.
  • Most units come with a 25 year guarantee for the cylinder.
  • Can be supplied in a horizontal model which allows you to fit them in lofts and roof eaves.
  • They come in all sizes so no matter how big or small your house is we will find the right set up for you.

What are the disadvantages of having an unvented cylinder? 

  • They are more expensive to install.
  • If your main water is turned off you lose water to all your house (as they are mains fed).
  • They need an annual servicing to check the safety devices on the unit.

What if I have poor mains water pressure?

This can be overcome by installing cold mains booster pumps and accumulators cylinder to hold cold water at pressure to supply your house. This is common in houses with three or more bathrooms.

Can we install an unvented cylinder in my house and how much does it cost?

An unvented cylinder can be installed in virtually any instance with a few modifications to your existing water system.

Costs vary depending on the set up so your best bet is to contact us and book in an engineer for a free no obligation quote. 


So if you’re tired of a humming shower pump, showering under a trickle of water or replacing that electric shower then maybe an unvented cylinder is the way forward for you.


Call 01424 200005 today for a free no obligation quote or advice.

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