A highly efficient proportional/modulation based solar PV hot water system at an affordable price. It diverts 100% of your surplus power to heat water & works even on cloudy days.

Designed and Made in the UK


Modulation based solar PV surplus energy manager that monitors in-house usage and PV power production to divert almost all the available surplus power to the immersion heater to heat water. Its intelligent sensing technology prevents the export of surplus power to the grid for negligible returns and uses it for local consumption, meaning you can avail hot water free of cost!

Other features


Inbuilt override/boost facility to turn on the immersion manually if required.


SolarImmersion works with all sorts of grid-tied micro generation systems.


Use the free surplus power from solar PV for hot water even in winter.


Gas boiler works far less than normal, helping you to save on energy bills.


No need to change the immersion heater or hot water tank to use SolarImmersion.


SolarImmersion can drive multiple loads, so when the water is hot enough and the thermostat cuts off, a second load could be activated.

SolarImmersion- It’s Green, It’s Intelligent, It’s Affordable

It Helps You Save Over £200 Per Year.

It’s the perfect solution to make the most of your PV installation & self-generated power. Take control of your generated power to save energy and make financial savings. Use the excess energy generated from a Solar PV/Hydro/Wind Turbine to heat your water for free.

It makes financial sense to use that extra power generated by your PV to heat water rather than exporting to the grid, as buying electricity and gas from the grid for heating water remains expensive. If you are on a feed-in tariff, you will still be paid for the power used to heat the water. Make the most of your feed-in tariff – use surplus electricity generated from your solar PV system for hot water and still receive payment for it!

  • Get hot water using the surplus from your existing solar PV.

  • Save money and improve the efficiency of your solar PV.

  • Reduce bills and still get your FIT payouts.

  • Reduce CO2 emissions.

  • Even works on cloudy days.

  • Use the solar PV power surplus in-house to heat water using SolarImmersion and prevent the unwanted export of electricity.

  • Doesn’t affect the solar PV system warranty.

  • The investment on SolarImmersion could pay itself back in less than 24 months.

  • Designed to last 25 years.

  • Maintenance-free with no moving parts.

  • Inbuilt overheating protection.

  • No plumbing alterations required.

British Made Quality Product

At SolarImmersion we are proud to design & manufacture all of our products in the UK to the highest standards.
Want to see production pictures ? Click here


SolarImmersion includes both the proportional controller and relay to dive the load. These options could be used independently or together. This powerful feature gives the option to drive any type if loads with SolarImmersion. For example, resistive loads like immersion heater could be controlled by the proportional controller while inductive loads with electronic components can be controlled by the relay.

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free hotwater with solarimmersion
Hot Water

SolarImmersion will divert the surplus power from renewable energy sources proportionally to an immersion heater for hot water or to a fan heater for room heating.

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undefloor heating with solar surplus power
Underfloor Heating

Make your underfloor heating to work with free solar surplus power using SolarImmersion. Underfloor heating can be connected as a primary or secondary load.

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battery charging with solar surplus
Battery Charging

The relay option with a secondary load feature in SolarImmersion makes it compatible with a battery charger to store the surplus solar power in a high capacity battery.

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High Efficiency & Performance – Use Almost 100% of Surplus.

The highly efficient SolarImmersion controller can divert almost 100% of the surplus power to the immersion heater or any other resistive load. The switch can also be re-configured to set the export level from 0 to 100W. Below is the graph showing the difference SolarImmersion makes when installed with a solar PV system.

solarimmersion comparison

SolarImmersion – A Valuable Addition to Maximise the Return from Your Investment.

Maximise the usage of your solar PV/Hydro/Wind investment by maximising the energy usage at point of generation and reducing the import/export. SolarImmersion helps you avoid the wastage of energy, control the export and store almost all surplus power as hot water.

Reviews & Testimonials

Check out what our customers are saying

All of our testimonials below are from real SolarImmersion customers and can be verified via a trusted third party service. Contact us for more info.
Excellent service - unit installed and working well - plenty of free hot water
Customer testimonial 1
Why didn't i buy it before ? - A Fantastic Investment -Bargain Price
Customer testimonial 2
Excellent transaction enjoying free hot water
Customer testimonial 3
Great item, simple to install.Piping hot water. Best price
Customer testimonial 4
Great service & working fine - just need some sun...
Customer testimonial 5
Thanks I now have free hot water off my solar panels:)
Customer testimonial 6
Easy install. Currently working well - seems good quality. Thank you!
Customer testimonial 7
Does exactly what is says on the tin! Works a treat!
Customer testimonial 8
Fantastic device, really works well. Very fast delivery and good communications.
Customer testimonial 9
Fitted on Tuesday and works a treat! Thanks a mil!
Customer testimonial 10