Solar panel coast view

Solar hot water

Turn sunshine into hot water

Our solar hot water solution gets you even more from your solar PV system by using excess energy to heat your water, rather than sending that energy to the grid.

Buying energy to heat your water can get expensive, but solar power is free once you’ve paid for its installation. So, it makes sense to make the most of your solar power, for your purse and for the planet. We can help you do this by installing a clever add-on called an immersion diversion device.

hot water solar panels
Zappi app

How does the immersion diversion work?

The system we install, the Eddi, is intelligent. So, only excess solar power is used to heat your water tank. The Eddi works by continuously measuring your solar generation and your household consumption and then diverting any excess energy to your hot water immersion heater.

The system will adjust the flow of energy to your immersion heater in response to changes in your solar generation and your consumption, as you go about your daily life.

Solar Water Heating

How much hot water can you generate?

A well-designed and sized solar PV system paired with an immersion diversion device can provide up to 70% of your annual hot water requirements. So, you could make huge savings.

In the summer you can expect to heat a full tank of water if your daytime usage is low. In winter, excess energy generation will still preheat your water.

So, you’ll be saving throughout the year.

domestic solar panels

What about solar hot water panels?

Solar hot water (or solar thermal panels) were a popular way to use the sun’s energy to heat water. Many households still have solar thermal systems.

Nowadays, we recommend a solar PV system paired with an immersion diversion device, due to:

  • Cost: the cost of solar PV panels, which generate electricity, has come down hugely in recent years. But, the cost of solar thermal has remained stable. So, solar PV panels generally make more economic sense.

Sally Gaydon
SunGift Customer
The work SunGift carried out on our property was extremely slick and professional, with every aspect of the system being carried out to the highest standards. We can’t fault SunGift in any way and we recommend them to everyone we know who expresses an interest in renewable energy.
Eddi device

Which device should you choose and how much will it cost?

We recommend the Eddi device. There have been a few devices available over the years and we’ve found the Eddi to be the most reliable and efficient. Also, the Eddi also has more customisable features and is fully compatible with battery storage, unlike its competitors.

Installed prices for an Eddi start from £680. If the system is installed at the same time as solar panels or battery system, the installation cost of the Eddi is reduced.


To have the Eddi installed:

  • you’ll need to have an immersion heater installed as part of your heating system; and
  • you mustn’t have solar thermal hot water panels already

You can have an Eddi installed along with a solar PV system or you can add one onto your system later.

To talk to one of our team about an Eddi, just get in touch.

Check out our awards

Case studies and news stories

Pat and Martin Williams
Malcolm Waite
Tyrone France