Gallery Joulia-Twinline 1
Gallery Joulia-Twinline 1
December 2020
Headquarters 2503 Biel/Bienne, Switzerland

Joulia-Twinline - A simple yet ecological shower drain with heat recovery

The impressively simple Joulia-Twinline technology proves that there is another way. By means of an ingenious heat exchanger module, the heat energy of the used shower water is reused to warm the incoming cold water mains. Thanks to this technology, the cold water arrives at the mixing valve up to 20°C warmer than before (from 10°C up to 30°C). Therefore, substantially less hot water is needed. By this simple means, a 4-person household can save about 1900 kWh per year. Joulia-Twinline is particularly performant in places where many people shower, such as sport centres, gyms, hotels or clinics. A single Joulia- Twinline can generate about as much heat energy as a 15m2 photovoltaic array would produce in one year (1'900 kWh/a). Showering with a clear conscience is thus both ecological and delightful. The sophisticated technology is concealed under a simple stainless steel cover. Because the heat exchanger cover also serves as a trap, the total installation height is comparable to conventional shower drains and can also be used in renovations. The technology is practically instant and cleaning is simple thanks to the easily-removable cover.

  • /

Key features

  • The drain doesn't emit any CO2 in the atmosphere, doesn't use any electric energy, just works by water flow
  • Save as much energy as 15 m2 of solar panels would have produced, whilst showering
  • Joulia-Twinline wins up to 60% of the normally lost energy back
  • Joulia-Twinline can be recycled by almost 100%
  • No impact on health


  • Joulia-Twinline saves up to 60% of thermal energy with each warm shower
  • A 4-person household can recover arround 1'900 kWh per year

Categories of Application

Activity Region

  • /
  • Headquarters
  • Activity

The information set out above, is solely for the purposes of information and the Solar Impulse Foundation does not provide any guarantee as to its authenticity, completeness or accuracy. This information does not constitute investment advice or a recommendation to buy into, transact or to enter into any agreement with any of the parties or persons mentioned above. Potential investors or interested parties are solely responsible for their investment or business decisions and for performing any due diligence required by the circumstances.