What is a solar PV diverter?

What is a PV Diverter?

A PV Diverter is an electronic device that allows users to divert excess solar energy their PV system generates to power other appliances. A good example of this is diverting excess energy to an immersion heater, to heat hot water for free.

Why Use A PV Diverter?

Most homes won’t use all the energy their solar PV system generates, resulting in surplus energy being sent back to the grid. As it stands the best price for exported energy is 10p per kWh (see our SEG/Export League Table for current rates) and import is currently around 16p per kWh. Hence if possible then it’s best to make the most of the energy your solar PV system generates in real time.

Without a PV diverter a solar PV system will either

• Generate insufficient energy for your home – in this scenario you will end up importing energy from the grid to meet your home’s demand.
• Generate surplus energy which will be sent back to the grid.

A solar PV diverter works by using a sensor that constantly monitors your solar PV system’s output against how much energy your home actually needs.

If your home is not demanding energy then rather than exporting the energy back to the grid the PV diverter will kick in, diverting energy to typically power an immersion heater.

Some diverters for example MyEnergi’s ‘Eddi’ will allow users to prioritise what receives the excess solar energy first. This is ideal for homes with a solar battery and immersion heater for example, giving users the option to choose where energy is distributed. Once complete the PV diverter will default to sending excess energy back to the grid.

Some PV diverters like Myenergi’s ‘Eddi’ come with a ‘boost’ function which can be activated when your solar PV system is failing to reach the demands of an immersion heater. In this scenario the PV diverter will switch modes and begin importing the extra energy required from the grid.

What are the advantages of a PV Diverter?

• A PV diverter will allow you to benefit from free-hot water for your home.
• A PV diverter is a ‘bolt-on’ device and can be retrofitted to a solar PV system.
• A PV diverter can be fitted to work with a heat pump or a traditional system boiler with a hot water cylinder.
• A PV diverter could help you to save money by limiting the amount of energy you import from the grid.

How much does a PV Diverter cost?

To give you an idea of costs we have listed (in the table below) three of the most popular market-leading PV diverters, all manufactured in the UK.

Brand	Cost	Website
Name: Eddi from Myenergi	Cost: £435	Website: https://myenergi.com/product/eddi/ (link opens in a new window)
Name: Solar iBoost from Marlec	Cost: £369	Website: https://www.marlec.co.uk/product/solar-iboost/ (link opens in a new window)
Name: SolarEdge diverter	Cost: £427	Website: https://www.solaredge.com/uk/products/smart-energy/smart-energy-hot-water/ (link opens in a new window)

Solar PV diverter prices correct as of December 2022.

How is a PV diverter fitted and how much will it cost?

A PV diverter is a small device that can usually be found fitted close to a hot-water cylinder. Two current transformer clamps are then fitted, one around your solar PV AC cable and the other around your incoming mains supply. This allows the device to monitor solar PV output and any surplus energy that is exported back to the grid.

Should you wish to have a PV diverter fitted as part of your solar PV installation then this will typically add around £800 to the total cost.

Conclusion

A solar PV diverter is a worthy addition to any solar PV setup. It allows you to make the most of the green energy you generate, whilst helping to reduce your carbon footprint and energy bills.

In addition to this solar PV diverters have a relatively small payback period, with most paying for themselves in just two years – making them a smart investment.