Warm feet on Mount Everest

Wafe Technology

A new foot warmer, devoid of electronics, fully autonomous and easy to use: this was the vision of the start-up company Wafe Technology. The heat sole “Chili Feet”, developed in collaboration with QUO, ensures that adventurer and extreme mountaineer Evelyne Binsack does not get cold feet on her way to Mount Everest.

Cold feet are uncomfortable

Frosty outside temperatures during the fall and winter months are the primary cause of cold feet. Not surprisingly, the market is awash with products to address the problem. However, they all have weaknesses: disturbing electronics, one-time application or time-consuming regeneration. Wafe Techology wanted to do away with all these issues with its new, autonomous foot warmers. To that end, QUO developed a concept solution that excels in simplicity.

Conversion of kinetic energy into heat

A special polyurethane foam converts part of the kinetic energy during walking directly into heat. Together with an industrial partner, QUO developed a material specifically designed for this application. For material characterisation, QUO developed a test bench whereby mechanical and thermal properties of PU foams can be analysed. In a complex, iterative process, engineers optimised material stiffness, damping and relaxation so that it produces maximum thermal output through the natural gait cycle. Measurements on optimised foam have shown that a 60-kg person can achieve a thermal output of up to 2.5 W while walking. This corresponds to the performance of a battery-operated foot warmer.

The foot warmer is available since December 2012 under the name of Chili-Feet and can be purchased online at www.chili-feet.ch.


Enthusiastic consumer feedback
Heat generation within minutes
Foot warmers without electronics and battery
Performance comparable to a battery-powered unit


Requirements analysis
Concept development
Prototyping and testing
Identification of manufacturing partner and market introduction support

Project Duration

24 Months

Core Team

3 Employees