Welcome to CET’s fact-filled website!

Here are the three main categories of the CET team’s work. Feel free to explore our topics.

The Built Environment and its Relationship to Environmental Therapeutics

Across the world, daylight is available all year round in sufficient intensity, color composition and spectral distribution to support our health and wellbeing. To be precise, across the year we all have 4,380 hours daylight, no matter where we are situated in the world. Not surprisingly though, these 4.380 hours are quite unevenly distributed during the year, depending of the latitude. Thus, the day-night cycle and the summer-winter cycle is a fundamental part of our life, with several documented health effects. Studies have shown that outdoor activities in daylight, such as morning walks, together with light therapy, provide significant benefit for people suffering from depression. Likewise, outdoor fresh air is available all year round and has positive effects on sleep and general activity and wellbeing.
However, in the western world we spend more than 90% of the time indoors, occupying the built environment and architectural environments with little planning for circadian daylight, improperly designed. We often receive too little or too low intensities of light as well as insufficient fresh air to sustain a healthy daily cycle. Although both daylight and fresh air are free and abundantly available to support our mood, energy, and sleep, we are not making the most of it when it comes to architectural planning that can support our daily behavior in the built environment.
Find out more in CET’s collection of original articles and other information:

Healing Architecture by Anna Wirz-Justice, PhD

We have been overwhelmed for the past year with images of nurses and doctors in intensive care units, wrapped in protective clothing as if on a space mission…

Can We Develop a Solar-Based Architecture? by Carlo Volf, PhD

The element of time is essential to architecture. To create buildings, we should study how human activity changes during the day and during the year.

How We Keep Our Circadian Rhythms from Drifting by Klaus Martiny, PhD

Imagine sitting out in space watching the earth gently rotate eastward on its axis, providing daily sunsets and dawns to all us 7.6 billion earthlings.

Environment Films

A film about light, architecture and health by Dr. Carlo Volf, showing variations in artificial light and daylight over a day and a year.

Circadian Environment Literature

Explore how light, timing, sleep, and built environments shape human biological rhythms. These resources help connect scientific findings with real-world design and wellness applications.

Interview with Leaders: Manuel Spitschan, PhD, Katharina Wulff, PhD, Lisa Heschong

These interviews offer valuable insight into how light and time shape health, behavior, and the spaces we inhabit.

Do you want more Body Clock information?

Check out our resources on this topic divided in three more categories related to Chronotype, Melatonin and Circadian Architecture.

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