Interview

Joulia: Showers with heat recovery

Joulia AG wants to put an end to wasting energy in the shower. The company has developed an innovative heat exchanger for showers that recovers thermal energy from used water.

With the Joulia AG heat exchanger, consumers can save energy costs, increase their energy efficiency and counteract global warming.

Which societal challenges does Joulia address?
Reducing energy consumption is not only important because of global warming, but also addresses the energy shortage in Switzerland emphasised by the Swiss Federal Office of Energy (SFOE). According to the SFOE, almost 50% of Switzerland's primary energy consumption is used for buildings. In buildings, heating and hot water in particular are among the energy drivers. These two drivers already require the same amount of energy in contemporary residential buildings.

However, the potential for energy efficiency in hot water recovery is hardly realised. Up to 80% of hot water in the household is used for showering alone, where it literally flows back down the drain after two seconds. In contrast, there are already many measures to increase energy efficiency in order to conserve space heating. Examples are improved thermal insulation of building envelopes and triple glazing of windows.

What is the solution?
Instead of flushing the heat of the shower water down the drain, the Joulia heat exchanger recovers the energy and ensures greater efficiency with less energy consumption. The Joulia heat exchanger is integrated into the shower floor and is not visible from the outside. Moreover, it works without electricity and ensures a clear separation between fresh and waste water. This is how it works:

The heat exchanger only extracts the thermal energy from the waste water that flows out; the used water still flows directly down the drain. The thermal energy gained preheats the cold fresh water and after only 10 seconds the heat is back at the shower mixer. In this way, consumers use up to 60% less energy without having to compromise on the warmth or length of their shower.

What are the challenges?
Initially, the challenges were to achieve high efficiency in heat recovery and to certify the product. Today, the challenges are more to promote the innovation to the market and to create awareness that heat recovery can make a significant contribution to energy efficient buildings.

What are the results (impact)?
Joulia recovers as much energy as about 8 m2 of solar panels (PV) produce per year. The energy savings result in annual savings of about 1'000 kWh for a 4-person household. Thus, consumers with heat recovery have lower ongoing energy costs. Depending on the shower channel model, it takes about 3-5 years until the additional costs of a shower with heat recovery are amortised.

What is Joulia AG's vision?
Joulia's vision is that showering with heat recovery will become the new standard. Economically, the company has also set itself the goal of further establishing the sales market in Switzerland and Holland in the next 5 years and expanding into other European countries.

Can the solution be multiplied and scaled?
The solution is scalable and multipliable because the company not only wants to sell showers with heat recovery itself, but also supplies the heat exchangers to partners who resell them. Thus, Joulia has great leverage to eventually reduce energy consumption in water heating.