Get a free, no-obligation quote. Call 07907 001 957 or request a call back — written quote after a home survey.
Strong, mains-pressure hot water to every tap
An unvented cylinder stores hot water at mains pressure, giving a strong, even flow to several outlets at once — without the cold-water loft tank a traditional vented system needs. RnR Renewables supplies and installs unvented cylinders, on their own or as part of a heat pump or boiler upgrade, installed in line with Building Regulations Part G3.
How an unvented cylinder works
The cylinder is fed directly from the mains, so stored hot water is delivered at mains pressure rather than relying on gravity from a loft tank. An expansion vessel and a set of safety controls manage the pressure and temperature as the water heats. The result is a powerful, balanced hot and cold supply that suits modern showers and multi-bathroom homes.
Why choose an unvented cylinder?
- Strong mains-pressure hot water, even with several outlets running at once
- No cold-water loft tank, freeing up loft space and removing a frost risk
- Works well with heat pumps, solar thermal and modern boilers
- Reliable, consistent performance for busy households
Installed to Building Regulations Part G3
Unvented hot water systems are covered by Building Regulations Part G3 because they store hot water under pressure. We install the cylinder with the required safety arrangements — expansion vessel, pressure and temperature relief, and a correctly run discharge — so the system is safe and compliant. We’ll explain the safety components and how they protect your home.
Correct sizing matters
An undersized cylinder runs out of hot water; an oversized one wastes energy keeping water hot you don’t use. We size the cylinder to your number of bathrooms and your household’s usage pattern, and check your incoming mains flow and pressure are sufficient — recommending alternatives if they aren’t.
What’s included
- Sizing for your household’s hot water demand
- Supply and installation of the cylinder
- Safety and discharge arrangements to Part G3
- Integration with your heat pump, solar or boiler
- Handover and a demonstration of the controls
Our process
- Survey, mains check and correct sizing for your home
- Written quote
- Installation to Part G3
- Commissioning, handover and servicing advice
Frequently asked questions
What size cylinder do I need?
It’s sized to your number of bathrooms and your usage pattern, confirmed at survey.
Will my mains pressure be enough?
We check incoming mains flow and pressure at survey and recommend the right cylinder, or alternatives such as an accumulator if the mains is weak.
Can I have an unvented cylinder with a heat pump?
Yes — heat-pump-compatible cylinders are part of most air source and ground source heat pump installations.
Does it need servicing?
Yes. An annual service keeps the safety components (expansion vessel and valves) working correctly; we’ll advise a sensible schedule.
What’s the difference between vented and unvented?
A vented system relies on a loft tank and gravity; an unvented system runs at mains pressure with no loft tank, giving stronger, more balanced flow.
How long does an unvented cylinder last?
A quality cylinder, correctly installed and serviced, lasts many years; we fit reputable brands with manufacturer warranties.
Related services
Often installed alongside our air source heat pumps, solar PV and gas boilers.
Get a quote for an unvented cylinder
Tell us about your home and we’ll arrange a survey. Call 07907 001 957 or request a call back.