Brighton & Hove · Sussex
Unvented Hot Water Cylinder Installation
Expert supply and installation of unvented hot water cylinders for homes and businesses across Brighton, Hove and the surrounding Sussex area.
Experience
That matters:
What is an Unvented Hot Water Cylinder
An unvented cylinder is a sealed hot water storage tank connected directly to the mains water supply – unlike older “vented” systems that rely on a cold water tank in the loft.
Because it’s fed by mains pressure, you get hot water at the same pressure as your cold taps – great showers, no pump needed.
Key points:
No cold water tank needed in the loft – saves space and reduces pipework
Mains pressure throughout – strong flow to all outlets simultaneously
Can be heated by a boiler, heat pump, solar thermal, or immersion heater
Requires a G3-qualified engineer to install – it’s a legal requirement because the system operates under pressure and has safety devices (pressure relief valves, thermostats) that must be correctly fitted
Typical size 150–300 litres depending on household size
The alternative – a vented cylinder – uses gravity-fed water from a tank in the loft, which gives lower pressure. Most modern installs favour unvented because of the pressure and the space saving.
Unvented Cylinder Installation
We handle everything from survey to commissioning. Our G3-qualified engineers install unvented cylinders to the highest standard, ensuring your system is safe, efficient, and built to last.
How installation works
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1. Survey & sizing:
We visit your property to assess your hot water demand, available space, and existing heating setup — recommending the right cylinder size, typically 150–300 litres. -
2. :
Removal of old system We safely decommission and remove your existing hot water cylinder or tank setup, including any redundant loft tanks if switching from a vented system. -
3. Cylinder & pipework installation:
The new unvented cylinder is fitted and connected to your mains supply and heating system — boiler, heat pump, or immersion heater. All safety devices are installed to Building Regulations standards. -
4. Commissioning & certification:
We commission the system, check all pressures and temperatures, and issue a G3 Building Regulations compliance certificate — a legal requirement for all unvented cylinder installations. -
5. Handover & aftercare:
We walk you through operating your new system and are on hand for any follow-up questions. Annual servicing is recommended to keep your cylinder running efficiently and your warranty valid.
We’ll ensure everything is installed safely, professionally, and ready for everyday use.
Cylinder Servicing & Maintenance
What's included in a service
- Inspect and test the pressure relief valve
- Test the temperature & pressure relief (T&P) valve
- Check pipework, connections and insulation
- Flush and check the strainer/filter
- Check and replace the expansion vessel pre-charge
- Inspect the thermostat and high-limit cut-out
- Inspect the motorised valve and controls
- Record findings and issue a service report
Signs your cylinder needs attention
Don’t wait for your annual service if you notice any of these – call us and we’ll investigate promptly.
- Water dripping or discharging from the pressure relief valve
- Drop in hot water pressure or flow rate
- Water not reaching temperature or taking much longer to heat
- Unusual noises — banging, rumbling or hissing from the cylinder
- Visible corrosion, leaks or damp patches around the unit
Cylinder Repairs
- Pressure relief valve Dripping or constantly discharging valves repaired or replaced before they cause water damage
- Expansion vessel Failed vessels cause pressure problems — we recharge or replace them as needed.
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Thermostat & controls
Water not heating correctly? We test and replace faulty thermostats and motorised valves. - Leaks & pipework We trace and fix leaks at connections, fittings and the cylinder body itself.
- Immersion heater Immersion heater element or stat failures diagnosed and replaced same visit where possible.
- Full replacement If repair isn't economical we'll advise honestly and handle a full new cylinder installation.
Our frequently asked questions
Find answers to our most frequently asked questions about hot water cylinders installation or feel free to get in touch.
An unvented cylinder is a sealed hot water storage tank connected directly to the mains water supply. Unlike older vented systems that rely on a cold water tank in the loft, unvented cylinders deliver hot water at full mains pressure — meaning powerful showers and strong flow to every tap, with no pump required.
Yes — a system boiler and unvented cylinder are the ideal combination. The boiler heats the water stored in the cylinder, and because the system runs at mains pressure you get consistent, powerful hot water to multiple outlets at the same time. It's one of the most popular setups in modern Brighton and Hove homes.
Yes — by law, unvented cylinders must be installed and serviced by a G3-qualified engineer. This is a Building Regulations requirement (Part G3) because the system operates under mains pressure and includes safety devices that must be correctly fitted and tested. All of our engineers hold this qualification.
Every 12 months. Annual servicing is a requirement of most manufacturer warranties and is strongly recommended for safety. A service includes testing the pressure relief valve, checking the expansion vessel, inspecting the thermostat and controls, and issuing a written service report.
The right size depends on the number of people in your home and how many bathrooms you have. As a general guide: 150 litres suits 1–2 people, 180–210 litres suits 3–4 people, and 250–300 litres is better for larger households or properties with multiple bathrooms. We'll recommend the right size during your free survey.
A straightforward like-for-like replacement typically takes one day. If you're switching from a vented system — which may involve removing a loft tank and additional pipework — allow one to two days. We'll give you a clear timeframe before any work begins.
Yes — we cover Brighton, Hove and the wider Sussex area including Worthing, Lewes, Burgess Hill, Haywards Heath and beyond. Get in touch to confirm we cover your postcode.
Ready for mains-pressure hot water?
Call now or complete our quick enquiry form to get started.
