fothermo
550 W solar immersion heater
Hot water from solar power. Less gas and oil.
550 W solar immersion heater for 1–2 people. Expandable up to 2,000 Wp.
- No electrician neededScrewed in and plugged in yourself in just a few minutes.
- Expandable up to 2,000 WpUp to 5 solar panels can be connected in parallel.
- Integrated MPP trackerAdjusts the heating power continuously to the available sun.
- Certified & made in GermanyDrinking-water compliant, IP24 protected, manufactured in Germany.
At a glance
Compact. Clever. Independent.
Technology
Thoughtful to the core.
Few, high-quality components – developed and manufactured in Germany.
Installation
Installed in minutes.
Screw in
Fits horizontally into your hot water tank with the standard G 1½″ thread.
Plug in
Connect the solar panels in parallel via solar connectors. No inverter, no electrician.
Done
The MPP tracker adjusts the power continuously and stops automatically at the target temperature.
Specifications
Every detail.
- Heating power
- up to 550 W
- Recommended PV power
- 800–1,600 Wp
- Maximum PV power
- 2,000 Wp (up to 5 panels)
- Panel voltage
- Voc < 50 V, panels in parallel
- Thread
- G 1½″ (6/4″)
- Length / immersion depth
- 470 mm / approx. 300 mm
- Maximum temperature
- 65 °C factory setting, adjustable up to 85 °C
- Protection class
- IP24
In the box
- 1× 550 W solar immersion heater
- 1× operating manual
Downloads
- Datasheet 550 W Solar Immersion Heater Preview & download
FAQ
Frequently asked questions.
Which heating systems is the 550 W solar immersion heater suitable for?
As a supplement to gas, oil and pellet heating as well as log boilers. Your existing heating stays in place – the 550 W solar immersion heater takes over part of your hot water as soon as the sun shines.
Will the 550 W solar immersion heater fit my tank?
The 550 W solar immersion heater has a standard G 1½″ thread (also called 6/4″). Total length 470 mm, immersion depth around 300 mm. Check the thread on your tank before buying.
Which solar panels do I need?
Panels with an open-circuit voltage below 50 V (Voc). 800–1,600 Wp is recommended, with a maximum of 2,000 Wp using up to 5 panels. The panels are connected in parallel – a series connection will damage the device.
Do I need an inverter, battery or 230 V connection?
No. The 550 W solar immersion heater connects directly to the panels and works independently of the grid – even during a power cut.
Does it work when it's cloudy?
Yes. Panels also generate power in diffuse light, just less. The integrated MPP tracker adjusts automatically. If there isn't enough sun, your existing heating takes over as usual.
Hot water, paid for by the sun.
We'll advise you personally – and find the solution that fits your home.