Upgrading from a Vented to an Unvented Cylinder
This page is about the upgrade decision specifically: whether it's worth swapping a working gravity-fed vented cylinder for a mains-pressure unvented one, not the general difference between the two types..
This page is about the upgrade decision specifically: whether it's worth swapping a working gravity-fed vented cylinder for a mains-pressure unvented one, not the general difference between the two types.
When staying vented is the right call
If the incoming mains flow rate is modest, an unvented cylinder won't deliver the strong showers people expect from one, and the vented cylinder's low running risk stays an advantage.
When upgrading pays off
A good mains supply, a loft you want cleared of tanks, and a household that wants equal, strong pressure at every outlet without a pump.
Which wins when
Test the mains flow rate before promising anything. A weak supply makes the upgrade a waste of money regardless of how good the new cylinder is.
What we check before recommending the switch
- Static and running mains pressure and flow rate
- Space and structural support for the new cylinder
- Discharge route for the safety valves
Who does the work
- Gas Safe registered engineers — registration 554328
- Worcester Bosch accredited installer
- John The Plumb Ltd, company registration 10026483
Ask about upgrading your cylinder
Tell us your current setup and we'll test the mains supply before recommending a switch either way.
Questions we get asked
Will an unvented cylinder definitely fix weak showers?
Only if the cause is the cylinder rather than the mains supply. We measure flow before quoting so you're not paying to solve the wrong problem.
Is the installation notifiable?
Unvented hot water installations require someone competent in that specific area and the work should be notified where Building Regulations require it.
Can the old cylinder be reused elsewhere?
Occasionally, if it's in good condition, but most vented cylinder removals are because the old unit is at the end of its life anyway.