SOLiC 200 Review UK: Price, Specs & Verdict

The SOLiC 200 is a solar immersion controller: a small, British-made unit that sends surplus solar power to your hot water cylinder's immersion heater instead of letting it export to the grid. It is one of the older and simpler products in the UK diverter market, with no app, no Wi-Fi and a long return-to-base guarantee. This SOLiC 200 review uses the maker's own user guide and brochure plus a current UK retailer listing to cover how it works, what it needs, what it costs and where it falls short.

How the SOLiC 200 works

Earthwise Products' user guide describes it as a proportional controller: it detects when the house is exporting power and offers an equal amount to the immersion circuit. Its worked example is a house using 500W while the panels generate 700W, so the SOLiC 200 offers 200W to the immersion. It checks export continuously and aims to keep it at zero. Because the power is varied rather than switched fully on or off, even a small surplus pre-warms the cylinder.

The financial logic is the same as for any diverter. Exported power earns a Smart Export Guarantee (SEG) rate set by your supplier, while heated water displaces gas or electricity you would otherwise buy later. See the Ofgem SEG overview for how export payments work, and our solar diverter vs battery vs EV charging guide for where surplus is best sent.

Key specifications

• Target load: a standard 3kW domestic immersion heater (Earthwise user guide).
• Supply: 230–240V AC single phase, 50Hz.
• Sensing: a wired load sensor (clip-on clamp) around the neutral or live meter tail, extendable to 5m. The brochure says it can be set up to measure either generation or export.
• Boost: one button gives full mains power to the immersion for 90 minutes, whatever the solar output. The brochure also lists a 30-minute pause function.
• Size: about 161 x 103 x 46mm and 475g per the brochure; the current retailer page lists 161 x 105 x 57mm.
• Display: three indicator lights (mains, sensor, immersion). There is no screen.
• Guarantee: 10-year return-to-base, with a condition covered below.

The maker's brochure and the retailer's page do not agree on every figure. The brochure lists a 40A maximum continuous load current, the retailer page 16A. Neither changes the practical limit: the user guide says the unit is designed for a 3kW immersion, so do not plan on anything larger.

Installation: what you need

A cylinder with a 3kW immersion on its own circuit. The quick-fit guide says the immersion circuit must not power any other appliance. A combi boiler has no tank, so there is nothing to heat.

A qualified electrician. Mount the unit close to the consumer unit and supply meter with 3cm clearance, wire it to the diagram, clip the sensor round the meter tail and commission it. The guide's commissioning steps need the house drawing at least 200W, and the sensor clamp has to face the right way: if three red lights show, you turn the clamp over and try again. Earthwise says installation typically takes under an hour.

The postcard. The 10-year return-to-base guarantee only applies if the enclosed postcard is completed and returned within 28 days, signed by a qualified electrician at the time of installation. The guide does not say what cover applies otherwise, so ask your installer to complete it on the day.

SOLiC 200 price in the UK

When we checked on 31 October 2026, Plug-In Solar listed the SOLiC 200 at £172 ex VAT, £206.40 inc VAT, but marked it out of stock, with no price date shown. Installed cost is that plus an electrician's time. That undercuts the myenergi eddi, which myenergi lists from around £439, and the iBoost+ at roughly £295. Treat the price as a snapshot and confirm stock before relying on it.

With a battery

A battery usually soaks up surplus before a diverter sees it. The retailer page describes a battery-aware setting with a 15-second activation delay and a 0–50W grid threshold, but gives no detail on how to set it, so ask your installer to confirm the behaviour with your specific inverter and battery. For prioritising between them, see our self-consumption guide.

SOLiC 200 vs the alternatives

• Price: cheapest of the mainstream diverters on listed prices.
• Smarts: none. No app, remote monitoring or tariff scheduling, so it cannot coordinate with an EV charger. The myenergi eddi adds all of that.
• Wiring: the sensor is wired, so the unit sits near the meter, unlike the wireless Solar iBoost+.
• Guarantee: 10 years return-to-base, longer than the eddi's three or the iBoost+'s two, if registered.

Our best solar diverter guide compares them side by side.

Legionella and weekly hot water

A diverter alone cannot guarantee that the tank gets hot enough in dull weather. Use the boost button or your normal heating controls so the cylinder reaches a safe stored-water temperature regularly, and ask your plumber for the right target for your system.

Verdict

Buy the SOLiC 200 if you have a plain 3kW immersion, the cylinder is near the meter, and you want the cheapest simple unit with a long guarantee and no app. Look elsewhere if you want remote monitoring, EV or battery coordination, or a wireless sensor. Note that the maker's brochure is dated and its stock position unclear, so check supply and ask your installer to register the guarantee.