Myenergi Eddi review

white and grey myenergi eddi unit on blue background

Myenergi is well known for its fantastic Zappi EV charge point but it’s not their first product. The Eddi solar diverter has that honour. The Eddi is an advancement of the Immersun solar diverter which was initially conceived by Myenergi founder Lee Sutton at his previous company 4eco.

The Myenergi Eddi is a device that is used as a way of diverting surplus energy from solar panels or wind turbines and using it to heat hot water.

Instead of diverting surplus energy back to the grid, and potentially selling it at a low rate, the homeowner consumes it, usually by heating a tank of hot water via an immersion heater.

Eddi hot water heating

The most common use for the Eddi is to connect to an immersion heater for water heating.

The Eddi is wall-mounted, usually next to the hot water cylinder, with up to two immersion heaters directly connected to the unit.

These heaters work sequentially with the immersion heater at the top of the cylinder heating up first, as hot water is drawn from the top of the cylinder.

Once this heater is satisfied via its thermostat then the lower heater will be switched on heating the rest of the cylinder.

If the cylinder only has one immersion heater it will still work fine, but it will depend on the placement of the immersion heater on how much of the tank is heated. The lower the immersion heater is the more hot water you will get.

Other uses for the Eddi

Obviously, hot water heating only works for people with an existing hot water cylinder, for those that have a combi boiler then the Eddi can heat electric towel rails, underfloor heating systems or any other resistive heating element instead.

The Eddi can also be connected to heat pumps to help with legionella prevention. For this an added relay module is required.

For a full overview of Eddi uses, it’s recommended to download the Eddi instructions as there are various setup options explained.Myenergi Eddi solar diverter in use

Eddi, how it works!

The Eddi works similar to the Zappi EV charger in that CT clamps are installed to monitor the energy being imported and exported. One is installed at the meter to monitor the grid supply, and another at the circuit breaker for the PV array/wind turbines.

Once enough surplus energy is generated the Eddi will divert electricity to the immersion heaters instead of sent back to the grid. This is more cost-effective as the cost to purchase electricity from the grid is higher than the price that it will be brought back at via a feed-in tariff/smart export tariff.

The Eddi is compatible with the Myenergi Harvi if a wireless CT clamp installation is required.

If a Zappi is already installed then the CT clamps for the Eddi will not be required as energy monitoring information is already obtained via the Zappi and transmitted wirelessly to the Eddi.


Priority control

The Myenergi Eddi is compatible with all Myenergi products such as the Zappi and Libbi battery. This integration means allows the user full control of where surplus energy is consumed, prioritising either the Zappi, Libbi or the Eddi.

In the Myenergi app priority is simply changed by swiping the Eddi icon to the top of the dashboard screen.

Setting the Zappi to priority means that surplus energy will go into charging an EV before it heats the water via an Eddi. Once the EV has enough charge then surplus electricity will automatically divert to the Eddi.

If surplus electricity is not being generated the Eddi can still be used as a conventional hot water timer. Timings can be set on the Eddi unit or via the Myenergi app, this enables overnight charging using a cheaper electricity tariff. A manual override switch is also on the Eddi unit.

Myenergi Eddi Design and Installation

The Myenergi Eddi unit is made from zintec steel with a white painted finish. It weighs in at 4.3kg which is quite heavy, so care needs to be taken when wall mounting the unit, especially plasterboard walls. We recommended using something like Gripit plasterboard fixings for this over standard cavity fixings.
Wall mounting is really easy. A detachable wall bracket is first fixed to the wall with 4 fixings, the Eddi then hooks on top of this and fixed in place with screws.
The Eddi measures 220 x 205 x 87mm so isn’t too large if installed in an airing cupboard. Consideration needs to be taken though for ventilation as its recommended to install with a 150mm gap above and below the unit for heat decipation.
Power input and output cables enter from the bottom of the unit and are held in place by cable clamps.


For water heating the Eddi is best connected to a 20A double-pole isolator switch as it is not recommended to install immersion heaters on 13A switched fused spurs unless they are rated below 3kW.

A setting can be adjusted within the Eddi to lower the output if it is installed on a fused spur for an immersion heater or lower rated resistive load.

The maximum rated heating element the Eddi can supply is 3.6kW.

The Eddi has an IP20 rating.

Myenergi Eddi connectivity

The Myenergi Eddi 2.1 now has full Wi-Fi and ethernet connectivity, as well as RF connection to the Myenergi Hub for users who have existing older Myenergi products.
If you have existing Myenergi products the Eddi can simply be paired as a slave device and receive over-the-air updates through the master device,
For Myenergi Hub users these updates will need to be forced and won’t update automatically like the newer Wi-Fi models.



Another great product from Myenergi that integrates well with the Myenergi eco-system helping make the most of your micro-generation system. The app makes the Eddi really simple to use, with the ability to change priorities at a swipe of a finger wherever you are in the world.

If you dont have other Myenergi products the Eddi is still a good choice as most other solar diverters do not the app control. Further Myenergi devices can then be added at a later date future proofing your system.


For Eddi installations in Shropshire and surrounding areas then contact us here. To find a Myenergi installer in other areas then visit the Myenergi installer page here

See our Zappi Review for more information about the Eddi compatible EV charger. Also see the soon to be released Myenergi Libbi home battery system here.