Fontus – Everything you need to know about the self-filling water bottle

Update: There have been reports of the Fontus project not being as efficient as advertised. We are looking into the credibility of these reports and will shortly update this article with any information we find. However, note that the technical details of the project reported here are accurate, and so are the scientific principles involved. We are just re-checking the viability and authenticity of its advertised claims. 

Imagine you went for a trek and realized that you have run out of the water to drink. What do you do? Fontus, a self-filling water bottle, can use solar energy to convert air into drinking water! The basic principle of this bottle is to absorb humid air, separate those water molecules from the air molecules, and obtain safe drinking water.


My intent was to invent the machine or device that would be able to filter the humidity in the air and turn it into drinkable water<span class="su-quote-cite">Kristof Retezár (designer of Fontus)</span>


Kristof was inspired to commercialize this product when the initial design of Fontus was shortlisted for the James Dyson Award in 2014.

By the year 2030, 47 percent of the global population will be living in areas of high water stress. These numbers are according to the UN. Fontus works ideally in humid weather as we need to convert moisture in the air into pure drinking water using a process called condensation.

Experiments were performed to pinpoint suitable conditions for the project. Based on the results of these experiments, it was noted that within an hour, 0.5 liters of water is produced by Fontus. This was achieved under temperatures between 30 to 40-degree Celsius and a humidity of 80 to 90 percent.

How does Fontus work?

For the process of condensation, hot and humid air is supposed to be cooled down.

The solar-powered device is contoured by a condenser to carry out this process. A small cooler, called Peltier Element, is also installed in the center of the device. The cooler is divided into two parts that are isolated and separated from each other. When the condenser is powered by solar electricity, the upper side gets cooled down and increases the temperature of the bottom side. The bottom side on cooling down helps the upper side to cool down even further. This is done by dissipating heat into the surroundings.

Think of it like this, a small amount of energy is used to cool down the upper part and heat the lower part (See Peltier Effect). Then due to the properties of the Peltier element, when the lower part (which acts as a heat sink) cools down, it cools down the upper part along with it. Less energy, more cooling.

When the upper chamber is invaded by air from the surroundings, it is slowed down by small perforated ‘walls.’ This action provides enough time for water molecules to be collected from it.



On extracting the water molecules from the air, the water gathers in the bottle through the pipe. You can attach any plastic bottle with a capacity of 0.5L. For drinking, the bottle can be easily removed from its holder and used accordingly. This self-filling bottle not only attends the requirements of long bikers and racers but also serves as a new method for collecting fresh drinking water in the drought-prone areas.



What’s next for Fontus?

Through the newfound fame and publicity from the presentation of Fontus at the James Dyson Award, Retezár wishes to set up a crowdfunding campaign. The Austrian government is financing the Fontus at the moment. The retail price for the Fontus is aimed at under $100. It could be commercially available in about 9 or 10 months.

Are there any drawbacks of Fontus?

One major drawback of this Self-filling bottle is that the water is safe for drinking until the air in that area is clean. But if the air is contaminated, the water also gets contaminated. Efforts are being made to overcome this problem.

Retezár has also released a stand-alone version that uses an inverted ventilator to suck air into the system. This is instead of relying on the airstream created from a moving bike. This next-generation version could be used in regions of the world where humidity is high, but water is scarce.

For more information, head over to this website.

6 thoughts on “Fontus – Everything you need to know about the self-filling water bottle

  1. Look up atmospheric water and atmospheric water generator has been used for years in other countries and the military.. you know they can make this on a small or large scale.

  2. This can not work and was debunked as a scam 2 years ago, They went bankrupt after spending all the backers money. The idea is great but is not functional. In the end it is just a de-humidifier. A very expensive one.

    1. Yep! That’s the latest update. It just seemed to good to be true. We are leaving the post up for informational purposes though.

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