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Photovoltaic hybrid boilers

Photovoltaic boiler with 1,500 W after-heating via the 230 V power supply when there is insufficient solar radiation.



1,500 W after-heating Powerful electric after-heating to be able to use sufficient hot water even on the darkest days.

Digital display on the boiler An LC display provides information about the system, e.g. B. the water temperature and the incoming solar power!

Warranty 3 year manufacturer's warranty

Cost-saving hot water thanks to almost free photovoltaic electricity. High profitability due to low initial investment costs and almost no operating costs!

Plug and Play The photovoltaic modules are simply connected using MC4 connectors.

70% energy savings A 2-person household can gain around 70% of the energy required for hot water preparation from the photovoltaic modules with an 80 liter photovoltaic boiler. The rest of the energy is drawn from the grid, especially in the winter months.

The photovoltaic hybrid boiler is the ideal solution for cost-effective and sustainable hot water supply in your home. Hot water accounts for 20-40% of the energy consumption in a household. fothermo boilers are the easiest way to use the sun's energy directly. Once installed, the boiler produces free hot water using the power of the sun. With its high performance, the photovoltaic boiler serves as a replacement for a classic electric boiler. The automatic reheating via the power grid in bad weather ensures sufficient hot water even on days without solar radiation.

The boilers are available in the sizes 30 l and 80 l. It is easy to mount on a wall. A pressure relief and non-return valve is also included. The water connection is made to two 1/2 inch connections with external thread. The solar connection is made via the MC4 connector system.

With up to 550 W, the photovoltaic hybrid boiler heats the water using photovoltaic electricity. In order to have enough water available even on cloudy days, up to 2,000 Wp photovoltaic output can be connected and / or the 230 V electrical after-heating can be used.


  • plug & play

    Easy installation. The photovoltaic modules are simply plugged into the boiler.

  • 550W + 1,500W

    550 W photovoltaic output and 1,500 W automatic after-heating via 230 V mains power on sunny days.

  • safety extra-low voltage

    Due to the low voltage level of less than 50 V, no electrician is required for installation.

  • Innovative MPP tracker

    50% higher yield thanks to the innovative MPP tracker, which always ensures the maximum yield of the PV modules.

1,500 W post-heating

In the event that for a long time there is not enough energy from the sun
can be provided to heat the water, the boiler can be on the
230 V reheating can be reheated automatically. To the post-heating
activate, a minimum temperature can be set on the boiler. For this is
turning a knob/thermostat on the boiler. For example, 35°C can be set
become. As soon as the temperature of the water reaches the set minimum temperature
falls below, the water is supplied with electricity from the mains at 1,500 W
reheated. The post-heating process ends automatically as soon as the water
has reached the set minimum temperature again.

The maximum water temperature of the boiler is 65°C. Is the 30 liter boiler
completely heated, this can be about 72 liters with 34 degree water, for example
showers can be removed. The 80l boiler delivers about 180 liters of 34 degree water
hot water.


The boiler is mounted on a stable wall with two screws.

The installation of the photovoltaic modules is very easy thanks to plug & play connections. The modules are plugged directly into the boiler using standard plug contacts (MC4). An extension cable can optionally be used to bridge larger distances between the photovoltaic modules and the boiler. (Photovoltaic modules and extension cables are not included in the scope of delivery, these can be purchased separately in the online shop.)

The water lines are screwed to a 1/2" standard thread.

possible applications

Replacement of a "normal" electric boiler

The photovoltaic hybrid boiler is like a "normal" electric boiler. But with a special feature: the free energy of the sun is primarily used.
As a rule, 60% - 80% of the hot water costs in a 2-person household can be reduced with the 80L hybrid boiler.

Tiny house / mobile home

Whether in a tiny house or in a mobile home. Wherever you need warm water, you can use the photovoltaic hybrid boiler.

Data sheet German
Datasheet English
operation manual
Which and how many photovoltaic modules?

Use excess energy from the boiler

Do not lose any energy and feed excess electricity into your home electrical network via the fothermo switching device and a standard micro PV inverter.

It also makes sense to oversize the connected photovoltaic module output of the boiler, since you can feed excess electricity up to 600W into the power grid.