History of solar water heating systems



18th century – Early development of solar thermal systems

The Swiss natural scientist Horace Bénédict de Saussure
builds a “simple solar water heater”, which is made of a wooden
box with a black bottom and covered with glass.
The solar collector reaches temperatures of almost 90 °C.


1890s – First solar water heater

The first commercial solar water heater is patented.

1900s – First thermosyphon system

William Bailey develops a more ergonomic, compact designed collector
and becomes the market leader in solar thermal technology.
The Bailey system is the first thermosyphon system
that places the tank on the roof and a collector underneath.


Bildergebnis für greenonetec thermosyphon


1920s – Collectors become flat

First flat-plate collectors for solar water heating are used.


1980s – Oil crises

Especially after the oil crisis, solar water heaters are becoming more and more popular in the USA.

2000s – Triumph of solar water heaters

The worldwide boom of solar water heaters begins.
Solar water heating systems become popular in China –
at least 30 million Chinese households have a system. 

2019 – World`s most revolutionary solar water heater

110 years after the first thermosyphon system,
SUNPAD starts a new era of solar water heater systems.
Solar energy has never been cheaper, simpler and more aesthetic!