Hot water · 4 min read
What is an unvented cylinder, and is it right for my home?
Mains-pressure hot water, no loft tank. How they work, who they suit and what they need.
What it is
An unvented cylinder is a sealed hot water tank connected directly to your mains water. It stores hot water under pressure, so every tap and shower gets a strong flow without a cold water tank in the loft.
How it works
Mains water enters the cylinder, is heated by your boiler or an immersion heater, and stays under pressure until you open a tap. Safety valves and an expansion vessel manage that pressure.
Is it right for you?
Usually, if you have two or more bathrooms, a busy household and decent mains pressure. If your mains flow is weak, a vented system or a different setup may suit you better. We test it before recommending anything.
Looking after it
Only qualified engineers should fit or service an unvented cylinder. It needs a yearly check of its safety valves and expansion vessel, which we can do alongside your boiler service.
