No gas connection, no flue, no annual service engineer. The Strom A.I.One pre-plumbed system arrives on site as a single factory-assembled unit — boiler, cylinder, pump, expansion vessel, and safety controls all pre-wired and pre-plumbed. It is one of the most practical all-electric heating solutions available for UK flats, new builds, and off-gas homes.
In this guide
- What is the Strom A.I.One?
- The technology inside — boiler and cylinder
- Why a hot water cylinder matters on electric systems
- Choosing your cylinder size: 150L, 170L, or 200L
- Choosing your boiler output: 6kW to 14.4kW
- Electrical requirements and supply considerations
- Installation: what pre-plumbed actually means
- Applications: flats, new builds, underfloor heating
- Shop our Strom A.I.One range
What Is the Strom A.I.One?
The Strom A.I.One (All-In-One) is a pre-plumbed electric heating package that combines two of Strom's most popular products into a single, factory-assembled frame: their compact heat-only electric boiler and the Prime2o unvented hot water cylinder, manufactured in their Ossett facility in West Yorkshire.
Rather than an installer assembling and commissioning these components separately on site, the A.I.One arrives ready to connect — the boiler is already mounted on the cylinder frame, pipework is factory-routed, the circulation pump, expansion vessel, and safety valve group are pre-fitted, and the electrical connections are pre-wired from boiler to the pump circuit. The result is a complete central heating and domestic hot water system in a single footprint, requiring only four connections on site: a cold mains inlet, a hot water outlet, a heating flow, a heating return — plus one electrical connection to the consumer unit.
The Strom A.I.One arrives factory-assembled: boiler, cylinder, pump, expansion vessel, and safety controls in a single unit — ready for four plumbing connections and one electrical connection.
Strom Limited is a British electric heating specialist based in Ossett, West Yorkshire. Founded with over 100 years of combined experience in the hot water and heating industry across their management team, they now supply through merchants across the UK and hold ISO 9001, 14001, and 45001 certifications as well as WRAS approval on their cylinders. Their heat-only boiler is certified to BS EN 12828, BS EN 14336, and BS 7671, and all installations require an NICEIC or equivalent competent-person Part P certificate.
The Technology Inside
The A.I.One is built around two distinct technologies working in combination, and understanding both helps you size and specify the right unit for a given property.
The Strom Heat-Only Electric Boiler
At the heart of the system sits Strom's heat-only boiler, available in four single-phase output ratings: 6kW, 9kW, 11kW, and 14.4kW. Unlike a conventional gas boiler where combustion and heat exchange are complex processes with many failure points, the Strom boiler uses a patented flat serpentine heating element — a direct-contact heat exchanger where water flows across the entire surface area of a multi-strand element rather than through a tube inside a separate tank.
Multiple independent heating strands share the load — less stress per strand, longer service life, no single point of failure
Output modulates down to as little as 1kW — avoids energy waste and reduces electrical demand spikes when paired with smart tariffs
Water never directly contacts the heating strands — dramatically reduces corrosion and limescale build-up on element surfaces
One moving part — the integrated three-speed pump. No combustion, no fan, no flue. Even at full speed the noise level is negligible
The element is a single replaceable unit — unlike competitor products with elements inside integral tanks, Strom's can be serviced indefinitely
Every kW drawn from the consumer unit becomes heat in your system — no flue losses, no standby pilot flame, no combustion by-products
The boiler operates between 20°C and 80°C flow temperature at system pressures of 0.5–1.5 bar, uses 3/4" male heating connections (Strom recommend flexible hoses to protect the internal pipework from torque), and the 15mm PRV is pre-fitted in the A.I.One package. A digital control panel shows flow and return temperatures, pump status, frost protection status, and whether the unit is actively calling for heat.
The Prime2o Unvented Cylinder
The cylinder half of the A.I.One is Strom's Prime2o indirect unvented cylinder, constructed from duplex stainless steel and guaranteed for 25 years against manufacturing defects. "Unvented" means it operates at mains water pressure — typically 2–3 bar for most UK properties — rather than relying on a gravity cold-water tank in the loft. This gives mains-pressure hot water at every tap and shower, with no roof tank, no risk of tank overflow, and no gravity-dependent flow rate.
The cylinder contains a single internal coil rated at 18.25–19.94kW (depending on cylinder size) through which the heating circuit water passes, transferring its heat to the stored domestic water without the two circuits ever mixing. The cylinder also has a factory-fitted immersion heater boss for a backup direct-heating element if required. Importantly, the A.I.One package pre-mounts the expansion vessel, temperature and pressure relief valve, and tundish discharge pipework — all items that commonly add time and cost when fitted individually.
Why a Hot Water Cylinder Matters on an All-Electric System
This is the most important concept for homeowners switching from gas to understand. On a gas combi boiler, hot water is generated instantaneously — gas ignites, the heat exchanger warms the water in real time, and as long as gas is flowing the system can satisfy unlimited simultaneous demand.
Electric systems fundamentally work differently. The electrical supply into most UK homes is single-phase at 230V. Even a 14.4kW electric boiler — the largest single-phase unit in the Strom A.I.One range — draws around 62 amps continuously at rated output. That is simply the physical upper boundary of what single-phase domestic wiring can deliver without a costly supply upgrade.
A cylinder solves the power limitation problem by decoupling energy input from energy delivery. The boiler heats the cylinder over a period of hours using whatever kW rating the electrical supply allows. The cylinder then stores that energy as hot water at mains pressure, ready to deliver it at full mains flow rate the moment a tap or shower opens — regardless of the boiler's instantaneous output. A 150L cylinder charged to 65°C holds roughly the same usable hot water energy as running a bath, a shower, and several sinks in succession.
There is a further advantage specific to all-electric homes: tariff flexibility. Smart electricity tariffs such as Octopus Intelligent, Agile, or Economy 7/10 offer significantly cheaper rates at off-peak times — often overnight between midnight and 7am. A cylinder programmed to heat during these windows stores cheap energy for use throughout the day, fundamentally changing the economics of electric domestic hot water. A combi electric boiler has no such ability.
The Strom Prime2o cylinder's heat loss specification matters here too. The 150L unit loses just 1.32 kWh per 24 hours — meaning a fully charged cylinder at 65°C at midnight will still be at usable temperature the following evening, even with no re-heating in between.
Choosing Your Cylinder Size: 150L, 170L, or 200L
The A.I.One is available with three cylinder capacities. The choice is primarily driven by the number of people in the household and daily hot water demand. A cylinder needs to be able to meet your total peak daily demand in a single charge — so it must be large enough to cover a morning routine without running cold.
150L
147 litres actual
Flats, studios, and 1–2 person households. Typically 1 bathroom, 1 shower, light daily demand. Ideal for BTR apartments and new build 1-beds.
| Actual capacity | 147 litres |
| Height | 1,075 mm |
| Width × Depth | 580 × 660 mm |
| Weight (full) | 196 kg |
| Heat loss (24h) | 1.32 kWh |
| ERP (cylinder) | B |
| Available boilers | 6kW, 9kW, 11kW, 14.4kW |
170L
167 litres actual
2–4 person homes. Suits a 2–3 bed house or flat with 1–2 bathrooms and regular daily showering. The most versatile choice for family homes.
| Actual capacity | 167 litres |
| Height | 1,203 mm |
| Width × Depth | 580 × 660 mm |
| Weight (full) | 220 kg |
| Heat loss (24h) | 1.63 kWh |
| ERP (cylinder) | C |
| Available boilers | 9kW, 11kW, 14.4kW |
200L
197 litres actual
3–5 person homes. Larger family households with 2+ bathrooms, frequent simultaneous showering, or a bath in regular use. Requires 11kW or 14.4kW boiler.
| Actual capacity | 197 litres |
| Height | 1,389 mm |
| Width × Depth | 580 × 600 mm |
| Weight (full) | 253 kg |
| Heat loss (24h) | 1.70 kWh |
| ERP (cylinder) | C |
| Available boilers | 11kW, 14.4kW only |
The A.I.One is a heavy unit when full of water — the 200L package reaches 253kg. Before installation, ensure the floor structure can bear this load, particularly in flats or upper floors. Your installer should carry out a structural assessment as part of the installation planning. The unit must be positioned on the floor (not wall-mounted) and the floor surface beneath must be non-combustible with a heat tolerance above 100°C.
Choosing Your Boiler Output: 6kW to 14.4kW
The boiler output determines two things independently: how quickly the cylinder recharges, and how much heat the boiler can provide to your radiators or underfloor heating circuits at any given time. These must both be considered — and importantly, they should be sized separately.
Strom's installation manual is explicit on this point: Part L 2022 of the UK Building Regulations prohibits significantly oversizing boilers, and because electric boilers are 100% efficient, an old gas boiler that was oversized for the property cannot simply be replaced like-for-like. A qualified installer must carry out a proper heat loss calculation for the property.
| Specification | 6kW26A draw | 9kW41A draw | 11kW48A draw | 14.4kW62A draw |
|---|---|---|---|---|
| Min. MCB breaker | 32A | 45A | 50A | 63A |
| Min. cable size | 2.5mm² | 6mm² | 10mm² | 10mm² |
| 150L cylinder | ✓ | ✓ | ✓ | ✓ |
| 170L cylinder | — | ✓ | ✓ | ✓ |
| 200L cylinder | — | — | ✓ | ✓ |
| Typical property size | Studio–1 bed flat up to ~40m² | 1–2 bed flat or house up to ~70m² | 2–3 bed house up to ~100m² | 3–4 bed house up to ~130m² |
The property sizes above are general guides only and will vary significantly based on construction type, insulation levels, glazing, and air permeability. An older poorly insulated 2-bed house may need more than an equivalent new-build 3-bed. A qualified heating engineer must calculate the actual heat loss before specifying boiler output. Oversizing is waste; undersizing means the property won't reach temperature in cold weather. Neither is covered under warranty.
Electrical Requirements and Supply Considerations
The Strom A.I.One operates entirely on single-phase 230V supply — the same domestic electricity supply used by all UK homes. There is no three-phase requirement, which is an important practical advantage over larger electric boilers and some heat pumps. However, the boiler does draw significant current, and the electrical installation has several requirements that must be met for both safety and warranty compliance.
| Specification | 6kW | 9kW | 11kW | 14.4kW |
|---|---|---|---|---|
| Rated voltage | 230V AC | 230V AC | 230V AC | 230V AC |
| Current draw | 26A | 41A | 48A | 62A |
| Minimum MCB | 32A | 45A | 50A | 63A |
| Minimum cable | 2.5mm² | 6mm² | 10mm² | 10mm² |
| Recommended cable type | H07 multi-strand high-temperature flexible cable | |||
| Isolator switch required | Yes — linked isolator, minimum 3mm contact gap in every pole | |||
| RCD considerations | High intentional earth leakage — may require dedicated RCD; measure before installation | |||
| Certification required | Part P certificate — NICEIC or equivalent competent-person scheme | |||
Because the boiler only needs to run during the cylinder heating cycle, pairing the A.I.One with a smart tariff such as Octopus Go, Economy 7, or Economy 10 allows the cylinder to be scheduled to heat exclusively during cheap overnight periods. At 7–15p/kWh off-peak versus 25–34p/kWh on-peak (illustrative 2025 figures), the running cost difference for domestic hot water alone is substantial.
Installation: What "Pre-Plumbed" Actually Means
The term pre-plumbed is used a lot in the industry but means different things depending on the product. For the Strom A.I.One specifically, the factory assembly includes the following — all of which would otherwise be individual line items in a conventional boiler-and-cylinder installation:
- Boiler factory-mounted to the cylinder frame in the correct orientation
- Heating circuit pipework routed between boiler flow/return and cylinder coil connections
- Circulation pump pre-fitted and pre-wired to the boiler PCB
- Heating expansion vessel pre-installed and pre-charged
- Pressure relief valve pre-fitted and positioned
- Cylinder temperature and pressure relief valve (T&P) pre-fitted
- Tundish and discharge pipe routing pre-set (installer connects the final discharge pipework to drain)
- Boiler digital display and control board factory-configured
What the installer still needs to provide on site: the four plumbing connections (cold mains in, hot water out, heating flow, heating return), the electrical supply to the unit (including cable, isolator, and MCB sized to the boiler output), an external thermostat and programmer, the automatic bypass valve on the heating circuit, zone valves if the system has more than one heating zone, and the tundish discharge pipework from the T&P valve to a safe disposal point.
Current UK Building Regulations Part L require that electric heating systems include zone control, room thermostats or programmable room thermostats, and thermostatic radiator valves (TRVs) on all radiators except the one in the same room as the room thermostat. Properties under 150m² can use a single heating zone with a 2-port valve; properties over 150m² require multiple independently controlled zones. The Strom installation manual provides Part L-compliant wiring diagrams for both configurations.
Typical all-electric installation for a flat: the A.I.One pre-plumbed system simplifies commissioning to four plumbing connections and one electrical supply.
Applications: Where the A.I.One Excels
All-electric new build flats and homes with no gas connection are among the strongest use cases for the Strom A.I.One. The pre-plumbed format is particularly popular with housing developers and BTR (build-to-rent) operators building multiple units with standardised electric heating systems.
All-Electric Flats & Apartments
The standout application. New build and converted flats with no gas connection need a system that works within single-phase electrical supply limits, fits in a utility cupboard, and delivers mains-pressure hot water with no loft tank. The A.I.One's compact footprint — just 580mm wide — and self-contained format make it ideal for service risers or airing cupboards in apartment blocks.
Off-Gas Grid Properties
Rural homes and properties beyond the gas network have historically relied on oil or LPG — fuels with volatile pricing, storage requirements, and no renewable pathway. The A.I.One on an off-peak electricity tariff, or powered by solar PV via an immersion controller, provides a genuinely competitive alternative with no fuel deliveries, no tank inspections, and no flue.
New Build & Development
Property developers and housing associations installing multiple units in a programme benefit disproportionately from the pre-plumbed format. A single consistent specification across all units reduces training burden, shortens commissioning time per unit, and simplifies aftercare. The 5-year Strom warranty (extendable to 10 years on registration) provides warranty continuity for the development handover period.
Solar PV Integration
The cylinder's direct immersion heater boss means an iBoost, Solar iBoost+, or compatible PV diverter can route surplus solar export directly into the cylinder's immersion element. This turns the cylinder into a thermal battery — storing solar energy as hot water during the day, free of charge. Fully compatible with Mixergy, MyEnergi Eddi, and other UK PV diverter systems.
Underfloor Heating
The Strom boiler operates across a flow temperature range of 20–80°C, making it entirely compatible with water underfloor heating (UFH) systems which typically run at 35–55°C flow temperatures. For multi-zone UFH with manifolds, a multi-channel programmer and zone actuators are required — all fully compatible with the Strom boiler's switch-live thermostat input.
Gas Boiler Replacement
Properties with existing radiator circuits and hot water cylinders that are removing gas boilers can use the A.I.One to replace both the boiler and cylinder in a single operation. The boiler connections are 3/4" male, familiar to any heating engineer, and the system design is analogous to existing S-plan or Y-plan configurations. A power flush of existing pipework and radiators is required before commissioning.
Strom are clear in their documentation about where electric boilers are not the right answer. High heat loss properties — older uninsulated homes with single glazing, solid brick walls, and no loft insulation — will have heating demands that push against the limits of single-phase supply and result in high running costs regardless of system efficiency. The right first step in those properties is fabric improvement: cavity or external wall insulation, double glazing, and draught proofing. Once heat loss is reduced, the A.I.One's sizing becomes straightforward and running costs become competitive.
Shop Our Strom A.I.One Range
We stock the full Strom A.I.One pre-plumbed package range at AIZO Quality Heating. Each unit is the genuine factory-assembled Strom product backed by Strom's 5-year boiler warranty and the Prime2o cylinder's 25-year manufacturing guarantee. All units are supplied with the installation manual; certification documentation is provided by the installing engineer.
| Cylinder size | 6kW boiler | 9kW boiler | 11kW boiler | 14.4kW boiler |
|---|---|---|---|---|
| 150L Pre-Plumb | ✓ SBSP6H150PP |
✓ SBSP9H150PP |
✓ SBSP11H150PP |
✓ SBSP15H150PP |
| 170L Pre-Plumb | — | ✓ SBSP9H170PP |
✓ SBSP11H170PP |
✓ SBSP15H170PP |
| 200L Pre-Plumb | — | — | ✓ SBSP11H200PP |
✓ SBSP15H200PP |
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Trade and Developer Enquiries
If you are specifying the A.I.One for a development of multiple units, a housing association programme, or a commercial property conversion, please request a custom quote. We can discuss volume pricing, staggered delivery scheduling, and can connect you with an NICEIC-registered installer network for project-scale work.
Request a Custom Quote Browse Electric Boiler RangeIf you're still researching whether an all-electric system is right for your property, our guides on running an electric boiler with solar panels, our electric boiler FAQ, and our underfloor heating FAQ cover the most common questions in detail. You can also explore our wider water underfloor heating systems for compatible products. For sizing and specification advice, get in touch with our team — we're happy to work through the right combination for your property before you commit to a purchase.