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G3 qualified engineer installing a Gledhill StainlessLite Plus cylinder in a London airing cupboard
Gledhill Approved · G3 Qualified

Gledhill StainlessLite Installation London

Plus and Pro range supply and fit across all 32 London boroughs. From £1,495 fitted for a 120L Plus, £2,495 for a Pro Heat Pump. 25-year tank warranty preserved with G3 install, Building Regulations Part G3 notification and Benchmark commissioning included on every job.

Like-for-like swaps from existing Megaflo, Heatrae Sadia and old Gledhill cylinders. Solar and heat-pump cylinders sized to MCS / MIS 3005. Same-day surveys in central London.

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25yr Tank warranty
G3 BPEC HWSS qualified
£5M Public liability
BS EN 12897 compliant
60min London response
Quick Answer

Gledhill StainlessLite is a duplex stainless steel unvented hot water cylinder range manufactured in the UK. The Plus range covers standard 120–300L domestic installs from £1,495 fitted. The Pro range adds twin-coil solar and oversized heat-pump variants from £2,395 fitted. Every install in London is G3 qualified, notified to building control, Benchmark-commissioned and carries a 25-year tank warranty.

What is a Gledhill StainlessLite cylinder?

The Gledhill StainlessLite is the company's flagship unvented hot water cylinder, made from duplex stainless steel and factory-foamed for low standing heat loss. Gledhill has been a UK cylinder manufacturer for over 90 years and the StainlessLite range is fitted in hundreds of thousands of homes — second only to Heatrae Sadia's Megaflo Eco in market share across Greater London.

The range splits into two families. StainlessLite Plus is the volume seller — single-coil indirect or direct-electric, sized 120–300L, designed as a like-for-like replacement for any unvented cylinder in a standard 1–5 bed London property. StainlessLite Pro is the renewable-ready family — Pro Solar has a twin-coil arrangement for solar thermal or PV-diverter hybrids, and Pro Heat Pump has an oversized single coil sized for the lower output temperatures of an air-source or ground-source heat pump under MCS rules.

Every StainlessLite ships with a 25-year tank warranty conditional on a G3 qualified install, Benchmark commissioning at handover and an annual service entered in the Benchmark logbook every year thereafter. We hold the G3 ticket (BPEC HWSS), the WaterSafe Competent Persons Scheme membership for Building Regulations notification, and full van stock of Gledhill-spec expansion vessels, PRVs, T&P valves and immersion elements for same-day repair across London.

StainlessLite Plus vs Pro — pick the right cylinder

Most London cylinder swaps are a StainlessLite Plus. The Pro range is the right call only when the property has a renewable heat source — or plans to add one within 12 months.

StainlessLite Plus

The volume seller. Duplex stainless steel, factory-foamed, 25-year tank warranty. Available 120–300L indirect (boiler-fed) and direct (electric-only). Sized for standard 1–5 bed London homes. The indirect Plus is the default specification we fit for like-for-like Megaflo and Heatrae Sadia swaps.

Best for: 1–5 bed homes, boiler-fed or twin-immersion, standard hot water demand.

StainlessLite Pro Solar

Twin-coil indirect cylinder with a lower coil sized for solar thermal or heat-pump and an upper coil for the boiler back-up. Twin sensor pockets, large coil surface area for low return temperatures, factory-set stratification. MCS-compatible for renewable grant applications.

Best for: Solar thermal hybrids, hybrid heat-pump setups, properties with PV diverters.

StainlessLite Pro Heat Pump

Dedicated heat-pump cylinder with an oversized single coil (≈3.0 m² on a 250L) so the heat pump runs at a low flow temperature without bottlenecking heat transfer. Larger volumes (210L+) only — sized to the simultaneous-use loadings under MIS 3005.

Best for: Air-source or ground-source heat-pump installs, MCS-grant applications, new-build heat-pump retrofits.

StainlessLite Plus Direct

Electric-only direct cylinder with twin immersion heaters and no primary coil. The right call for top-floor flats with no boiler, all-electric properties, and back-up cylinders. Available 120–250L. Heat-up times are longer than indirect — sizing matters more.

Best for: All-electric properties, top-floor flats, off-gas conversions.

Gledhill StainlessLite cost London — 2026 prices

Every price is supply and fit, fixed in writing on the day of survey, inclusive of VAT, materials, removal of the old cylinder, Building Regulations G3 notification and Benchmark commissioning. No hidden parts mark-up, no out-of-hours premium on scheduled installs, no call-out fee on quoted work.

JobWhat's includedFitted from
StainlessLite Plus 120L — supply & fit120L indirect cylinder, full G3 inlet group, expansion vessel, T&P relief, discharge pipework to outside, Building Regs notification, Benchmark logbook.£1,495
StainlessLite Plus 150L — supply & fit150L indirect cylinder, full G3 group, primary connections, discharge route, commissioning, certificate of compliance.£1,595
StainlessLite Plus 180L — supply & fit180L indirect cylinder (UK sweet spot for 3-bed terrace), full G3 kit, pipework alterations up to 2 m, commissioning.£1,745
StainlessLite Plus 210L — supply & fit210L indirect cylinder, G3 group, primary repipe in copper, expansion vessel sized to manufacturer table, full commissioning.£1,895
StainlessLite Plus 250L — supply & fit250L indirect cylinder for 4–5 bed homes with 2 bathrooms, full G3 kit, secondary return option, Benchmark logbook.£2,195
StainlessLite Plus 300L — supply & fit300L indirect cylinder, mains-pressure flow check included, full G3 group, primary connections, commissioning, certificate.£2,595
StainlessLite Pro Solar twin-coil — supply & fitTwin-coil indirect cylinder for solar thermal or heat-pump pairing. 180L–300L, MCS compatible sizing, dual sensor pockets.£2,395–£3,095
StainlessLite Pro Heat Pump cylinderHeat-pump optimised cylinder with enlarged coil surface area, low return temperatures, MCS-compliant sizing tables applied.£2,495–£3,195
Annual G3 service — StainlessLiteExpansion vessel pre-charge, T&P witnessed lift, PRV outlet pressure, anode inspection, thermostat function, Benchmark refresh.£155
Labour-only install (customer supplies cylinder)Fit your supplied StainlessLite cylinder, full G3 group, commissioning, Building Regs notification, Benchmark logbook.from £695

* Add £350–£500 for vented-to-unvented conversions (expansion vessel, G3 discharge route, loft tank removal). Add £100–£200 for awkward access. Full price list on the pricing page.

Get a fixed survey quote in your London property

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The install — five steps from quote to certificate

Gledhill StainlessLite Plus cylinder fitted with full G3 inlet group and expansion vessel
1

Survey and sizing

30–45 min

Free on-site survey across London. We measure dynamic mains pressure (bar) and flow (L/min) at the inlet, check airing cupboard dimensions for the StainlessLite footprint, plan the discharge route to a visible external termination, and confirm the right Plus or Pro variant against bedrooms, bathrooms and occupants.

2

Fixed-price quote

On the day

Written fixed price including cylinder, full G3 inlet group, expansion vessel sized per Gledhill table, T&P relief, tundish, discharge pipework, electrical isolation, removal and disposal of the old unit, Building Regulations notification, and Benchmark commissioning. No hidden parts mark-up.

3

Drain-down and removal

60–90 min

Existing cylinder isolated electrically and on the mains, drained through the lowest tap, lifted out. On Megaflo and Heatrae Sadia swaps the existing discharge and inlet group are inspected and re-used where compliant — Building Regs do not require new pipework if the route is sound.

4

Cylinder install

2–4 hours

StainlessLite positioned, levelled, primary flow/return connected in 22 mm copper, cold mains inlet through the new G3 group (stop, PRV, expansion vessel, check valve, balanced cold tee), T&P relief plumbed via tundish with 300 mm air gap, discharge piped continuously falling to outside above a gully.

5

Commissioning and Benchmark

45–60 min

System filled, vented, immersion (where fitted) wired through fused spur with RCD protection. Expansion vessel pre-charge confirmed at 3.0 bar with the system depressurised. T&P witnessed lift. Outlet pressure set to 3.0–3.5 bar. Stored water brought to 60°C. Benchmark logbook completed and emailed within 24 hours. Building Regs G3 notification filed via WaterSafe.

G3 compliance & Benchmark commissioning

Unvented hot water in the UK sits on a small stack of statutory rules and product standards. Every Gledhill StainlessLite job is documented against them in the Benchmark logbook that ships with the cylinder — the paperwork is what preserves the 25-year tank warranty.

Approved Document G3

Every unvented hot water storage system over 15 litres in England and Wales is a controlled service under Building Regulations Part G. We hold current G3 tickets (BPEC HWSS, renewed every 5 years) and notify every install to building control through our WaterSafe Competent Persons Scheme membership. Your Building Regulations Compliance Certificate is posted within 30 days.

BS EN 12897 cylinder spec

StainlessLite Plus and Pro cylinders are CE-marked to BS EN 12897 — the European product standard for indirectly heated unvented closed storage water heaters. Every cylinder ships with the four mandatory safety layers: a working thermostat, a non-self-resetting energy cut-out, an expansion device, and a temperature & pressure relief valve. We test all four at commissioning.

Benchmark commissioning

Gledhill warranty is conditional on a completed Benchmark logbook entry at install and at every annual service. We sign the install page on site, record the cylinder serial, inlet pressure, vessel pre-charge, T&P test, and date of commissioning. A scanned copy is emailed and the paper book stays with the cylinder for the next engineer.

Water Regulations 1999

All wetted components are WRAS-approved under the Water Supply (Water Fittings) Regulations 1999. Every install is notifiable to Thames Water (or your local water undertaker) when the system arrangement changes. We file the notification as part of the install fee.

BS 7671 18th Edition

Immersion heater circuits on the StainlessLite Plus Direct are wired to BS 7671:2018+A2:2022 — RCD protection on the final circuit, fused isolator to the immersion rating, supplementary bonding where required. Notifiable electrical work is signed off via our Part P registration.

G3 discharge sizing

The D1 copper discharge pipework from the tundish is sized one pipe size larger than the inlet to the T&P valve — typically 22 mm from a 15 mm valve — with a continuous fall, no more than three bends, and a terminating point to a visible external location at low level. Discharge into a void, soil pipe or hopper is a Building Regs breach and we will not sign it off.

Temperature and pressure relief valve and tundish on a Gledhill StainlessLite cylinder

Recent StainlessLite jobs across London

Five anonymised installs from the last six months — the variant fitted, the diagnostic, the final price. Every one was Benchmark-commissioned and notified to building control under our WaterSafe Competent Persons Scheme membership.

Edwardian semi, Clapham — Megaflo to StainlessLite Plus 210L

2009 Megaflo Eco 210L beyond economic repair — third PRV in five years and the expansion vessel leaking. Replaced with a StainlessLite Plus 210L indirect on the same primary pipework, new G3 group, new external 18L expansion vessel. Single-day install, Benchmark logbook completed. Cost: £1,895 inc. VAT, full G3 notification filed.

Top-floor flat, Islington — StainlessLite Plus Direct 150L

All-electric mansion-block flat, no gas, replacing a 1990s direct vented cylinder with loft tank. Loft tank removed, mains upgraded to 22 mm from the riser, StainlessLite Plus Direct 150L installed with twin immersions, Economy 7 wiring, fused spur with RCD. Cost: £2,195 inc. VAT, building control notified.

Victorian terrace, Hackney — StainlessLite Pro Solar 250L

Solar thermal install on a south-facing roof, paired with a system boiler back-up. StainlessLite Pro Solar 250L twin-coil cylinder with solar coil bottom-mounted and boiler coil top-mounted. Twin sensor pockets wired to the solar controller. MCS sizing tables applied. Cost: £2,895 inc. VAT, MPS paperwork completed for the homeowner grant claim.

1960s detached, Barnet — StainlessLite Pro Heat Pump 300L

Air-source heat pump retrofit replacing an old gas combi. StainlessLite Pro Heat Pump 300L with 3.0 m² coil, sized per MIS 3005 to the simultaneous-use loadings of a 5-bed family home with two bathrooms. Low-return temperature operation confirmed at commissioning. Cost: £3,095 inc. VAT.

New-build townhouse, Wandsworth — StainlessLite Plus 180L annual service

Three-year-old StainlessLite Plus 180L on a landlord PPM contract. Pre-charge dropped to 1.9 bar (target 3.0) — reset. T&P witnessed-lifted clean. PRV outlet pressure 3.3 bar (within Gledhill table). Anode inspected (75% remaining). Benchmark logbook refreshed and emailed. Cost: £155 inc. VAT.

Ready to book a Gledhill StainlessLite install?

Free on-site survey across London. Fixed-price quote on the day, work scheduled within a week, single-day install in most cases, Benchmark logbook signed and emailed on completion.

Call 0207 046 1363WhatsApp 07456 975436Book a survey

Frequently asked questions

What is the difference between StainlessLite Plus and StainlessLite Pro?
StainlessLite Plus is the standard duplex stainless steel cylinder range — single coil indirect or direct electric, sized 120–300L, fitted as a like-for-like swap on most London cylinder jobs. StainlessLite Pro is the renewable-ready range with two variants — Pro Solar (twin-coil, for solar thermal or PV-diverter hybrids) and Pro Heat Pump (oversized single coil, for air-source or ground-source heat pumps under MCS sizing). Pro cylinders carry the same 25-year tank warranty but cost £500–£900 more than the equivalent Plus, depending on capacity.
How long does a Gledhill StainlessLite installation take?
A like-for-like cylinder swap on existing G3-compliant pipework is a 4–6 hour single-day job. A first-time unvented install replacing a vented cylinder plus loft tank is a full day (6–8 hours) because the inlet group, expansion vessel, discharge route and electrical isolation are all new. Vented-to-unvented conversions in mid-floor London flats sometimes run two days where the discharge route needs to be cored through an external wall or run in a fire-rated duct.
Do I need a G3 engineer to install a StainlessLite cylinder?
Yes. Approved Document G3 of the Building Regulations makes unvented hot water installation, commissioning and modification a controlled service. The engineer must hold a current G3 ticket (BPEC HWSS, LCL Awards or City & Guilds 6189), the work must be notified to building control directly or through a competent person scheme, and the Benchmark logbook must be completed. Anyone working on a StainlessLite without a G3 ticket voids the 25-year Gledhill tank warranty and invalidates the home insurance.
What size StainlessLite cylinder do I need for a London home?
Gledhill's sizing table follows the HWA convention — 35–45 litres per occupant, plus 60 litres for each bath used daily, plus an extra 35 litres per bedroom. A 1–2 bed London flat with a shower is fine on a 120–150L Plus. A 3-bed terrace with one bath is 180L. A 4-bed home with two bathrooms is 210–250L. A 5-bed home, freestanding bath or HMO is 300L. Heat-pump installs go larger — typically 250–300L Pro Heat Pump to deal with the lower output temperature.
Is the Gledhill StainlessLite better than a Megaflo?
Both are duplex stainless steel cylinders with 25-year tank warranties and broadly comparable performance. The honest answer in London is that they are close enough that the difference is access to parts and engineer familiarity, not headline spec. Heatrae Sadia (Megaflo) has the broadest parts network in London — vessels, PRVs and elements are on most plumbers' vans. Gledhill StainlessLite has a slightly better recovery time on the Plus range and a stronger heat-pump offering on the Pro range. For most like-for-like swaps we will fit whichever the customer prefers.
What warranty comes with a new Gledhill StainlessLite?
25 years on the cylinder tank itself, 2 years on the parts (expansion vessel, PRV, T&P, immersion, thermostats). The tank warranty is conditional on installation by a G3 qualified engineer, a completed Benchmark logbook at install, and an annual service entered in the Benchmark logbook every year thereafter. Skipping a year breaks the warranty chain. We send annual reminder emails to every customer 30 days before the service is due.
Do you take the old cylinder away?
Yes. Removal and disposal of the old cylinder is included in every supply-and-fit price quoted. Old cylinders are taken to a licensed scrap metal recycler and we provide the WTN reference on request. We do not leave units in front gardens, communal areas or on the kerb. On mansion blocks where access is via service lift only we sometimes book the lift in advance — that does not add to the quoted price.
Will my old vented cylinder pipework work with a new unvented StainlessLite?
Some of it. The primary flow and return from the boiler usually transfer cleanly. The cold feed and vent from the loft tank are abandoned (they are not used on an unvented system). The hot distribution to taps and showers is re-used if it is in good condition and sized correctly for mains-pressure flow. The single critical new piece is the discharge pipework from the T&P relief — it must run continuously falling to a visible external termination and is not interchangeable with anything from a vented system.
Does the StainlessLite work with my system or combi boiler?
With a system or heat-only boiler, yes — the StainlessLite Plus indirect is wired through a motorised valve on the primary flow, controlled by a cylinder stat, exactly as it would be with any other cylinder. With a combi boiler, no — combi boilers heat water on demand and are not designed to charge a stored cylinder. If you want to keep the combi and add stored hot water, the route is usually a thermal store or to swap the combi for a system boiler at the same time as the cylinder install.
Can a StainlessLite go in a top-floor flat?
Yes — they are a popular choice in London top-floor flats because the unvented format removes the loft tank and the header tank noise that comes with it. The two pre-install checks are mains inlet pressure (must be at least 1.5 bar dynamic at the proposed inlet group) and a viable discharge route to outside. In some mansion blocks the discharge route is the hardest engineering question — the cylinder may need to live closer to an external wall than the previous airing cupboard, or the discharge piped in a fire-rated metallic duct under building control.
How much does a Gledhill StainlessLite annual service cost in London?
£155 fixed for a single cylinder, anywhere across London. The service is the manufacturer-mandated annual maintenance under the 25-year warranty terms — expansion vessel pre-charge tested and reset, T&P relief witnessed-lifted, PRV outlet pressure measured and adjusted if needed, anode condition recorded, thermostat cut-out function verified, Benchmark logbook entry made, and a service certificate emailed. Average time on site is 60–90 minutes. We send annual reminders to every customer on file.
What is the recovery time on a StainlessLite Plus?
On an indirect cylinder paired with a 24–32 kW system boiler, a StainlessLite Plus 180L recovers from cold to 60°C in about 25–30 minutes — fast enough to refill after a back-to-back shower load. The Plus 250L is closer to 35–40 minutes. On a direct cylinder with two 3 kW immersions running together, recovery is much slower — about 90 minutes on a 150L Direct. Pro Heat Pump cylinders run cooler stored temperatures and longer recovery times by design.
Do you notify building control for the StainlessLite install?
Yes. We self-certify every install through our WaterSafe Competent Persons Scheme membership. The notification is filed within 7 days of commissioning and the Building Regulations Compliance Certificate is posted to the property owner by WaterSafe within 30 days. There is no separate fee from the local authority and no need for the customer to apply for building control approval — the certificate is the proof a future buyer's conveyancer asks for.
Can I have a StainlessLite Pro Heat Pump cylinder fitted with my existing boiler?
It is possible but rarely sensible. The Pro Heat Pump cylinder has an oversized coil designed for the low flow temperatures of a heat pump (typically 50–55°C). Run from a conventional gas system boiler at 70°C+, the oversized coil works fine but the cost difference over a Plus is wasted — you are paying for heat-pump compatibility you are not using. Fit a Pro Heat Pump cylinder when you have a heat pump now or are installing one within 12 months.
What happens if my StainlessLite stops giving hot water?
Three quick checks before you call — first, is the boiler firing on hot water demand (look for a flame symbol)? Second, is the cylinder thermostat clicking when you turn the dial up? Third, has the immersion heater isolator tripped (on Direct models)? If all three look fine, the most likely fault on an indirect cylinder is a stuck motorised valve or a failed cylinder stat — both fixable within an hour at first visit. On a Direct cylinder it is almost always a failed immersion element or thermostat. Same-day callouts across London, fixed-price diagnosis on site.

Question not answered? Call 0207 046 1363 and speak to a G3 qualified engineer directly — no call centre, no triage.

Service area

Service Area — All London Boroughs

G3 qualified Gledhill engineers based in central London with same-day cover across all 32 London boroughs and the City. Average response time inside Zone 2 is 60 minutes for repair callouts; install surveys booked within 48 hours.

Book your Gledhill StainlessLite install in London

G3 qualified engineers, full Gledhill van stock, Benchmark commissioning, Building Regulations Part G3 notification, 25-year tank warranty preserved. Free survey across all 32 London boroughs.

0207 046 1363WhatsApp 07456 975436Book a survey

London 247 Home Services Ltd · Company No. 17120057 · £5M public liability · G3 BPEC HWSS qualified · WaterSafe Competent Persons Scheme

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