The solar PV field is creating a stir with regard to electrical energy storage systems (EES); meanwhile, increased attention has been focussed worldwide on an alternative and handy storage system: hot water.

The energy used for heating hot water for sanitary purpose (or other purposes) is a rather relevant item of expense in families, hotels, communities and factories, but it can be easily decreased thanks to solar panels and thermal storage.

Many houses are already equipped with electric boilers and hot water storage tanks, thus they can be upgraded thanks to solar PV plants and to new technologies to exploit the potential of renewable energies.

This is an interesting opportunity indeed: the use of clean energy for activating an immersion heater using self-consumption only, offers clear advantages to reduce the energy bills and the environmental impact.

Self-consumpition with Power Reducer

One of the many benefits of heating water with an immersion tank is that power consumptions can be monitored in real time, thus allowing to modulate the power absorbed by a load. This way, it is possible to use only the surplus energy produced by solar PV systems, without drawing any energy from the grid.

4-noks Power Reducer RC

4-noks Power Reducer control unit – designed and manufactured in Italy by Astrel Group – was specifically created to use at its best the immersion heater: Power Reducer exploits homegrown energy adjusting automatically and in real time the power diverted to the water heater depending on the surplus energy available, even few hundred watts.

The result? Self-consumption capacity can be dramatically increased, therefore immersion heaters can be used as real thermal batteries.

It goes without saying this has a great impact on energy usage and environmental footprint. For those who have (or will soon have) a solar PV plant, thermal storage may be one of the most convenient solutions to cut down energy bills.


Thanks to the free App “Elios4you”, super easy to use even for non-experts, the activation of the Power Reducer can be managed and customized depending on the user’s needs.

The immersion heater activation can be easily programmed via App with scheduled operating hours and thresholds, with real time view of the energy diverted to the electric boiler. If necessary, it is also possible to force the immersion tank to operate at full power, with a simple tap on your smartphone.

For those who are not interested in monitoring the whole solar PV plant but would just like to maximize the use of surplus energy producing hot water, Power Reducer is also available in its stand-alone version. With a built-in energy meter, this simple installation will deliver immediate savings.

Solar energy and technology are therefore the best allies for a more eco-sustainable lifestyle: with 4-noks Power Reducer the user can exploit at its best the clean energy produced by the solar PV system, using in an easy and efficient way the greenest storage system now available, hot water.

» Learn more about 4-noks Power Reducer