by Per Arnold Andersen, VELUX Group

Light from the sun travels 150 million kilometres to reach the Earth’s surface. Whether it also touches our skin and eyes, our soul and senses depends on our ability to filter and harness it with the envelopes that we use – be it clothing or buildings.

The relationship between the sun, people and the envelope is the theme of this issue of Daylight/Architecture. Starting with the cover image, we invite you on a journey from the soul to the sun and back again. The photographic essay by Susanne Wellm and Torben Eskerod illustrates the intimate relationship that both our inner and our outer world have with the light and energy of the sun, the essence of our lives as well as a source of mental and spiritual well-being. What is the purpose of architecture? The Roman architect Vitruvius answered this question with “firmitas – utilitas – venustas”, which can be translated into strength, utility and beauty. The building envelope serves to protect people from cold, wind, and rain (firmitas), to give people a comfortable and healthy indoor environment (utilitas), and to enrich people’s sensual perception (venustas). Furthermore, the building envelope interacts closely with the light and energy of the sun, and with people living in the house. Based on this premise, the current issue of Daylight/Architecture features the relationship between people, the sun and the building envelope as it evolves in the creation phase of buildings, during the operation of buildings, and in the evaluation of the experiences made when inhabiting a building.

For millennia, human beings have developed building envelopes to control and harness the sun’s light. By now, we tend to think we know everything about the building envelope and how it supports our health and wellbeing indoors. But how much do we really know? In the 19th century, it was uncommon for houses in most of Europe to be warmer than 16–18°C during winter. Today, most people seem to prefer temperatures of 22–23°C. In other parts of the world, the situation is different. “Most people in my country will consider it comfortable if the temperature in a room is five degrees or more below the outdoor temperature,” says architect, Francis . In Burkina Faso, where he was born, ‘comfort’ can thus be achieved at 30 degrees Celsius or even more, depending on the season.

Three architects – Diébédo Francis Kéré, Thomas Herzog from Germany and Peter Stutchbury from Australia – are portrayed in this magazine. They explain how their buildings, relate people to the sun and the local climate by means of intelligently designed building envelopes. These buildings employ the forces of nature in an intelligent way – and while providing protection, they connect the inhabitants to their outdoor environment and the sun. Rather than relying on air-conditioning for comfort, the three architects allow the indoor climate in their houses to fluctuate with the seasons. And recent science is proving them right; people in ‘free-running’ buildings have a much larger tolerance range in terms of temperature than in purely air-conditioned ones. They also suffer less from the symptoms of ‘sick-building syndrome’ – and, needless to say, buildings without air-conditioning also consume far less energy.

Still, the question remains: do naturally ventilated and passively-cooled buildings actually provide the degree of comfort that their designers intended them to? With these questions in mind, the VELUX Group has participated in the design, construction and evaluation of more than 20 demonstration buildings and Active Houses during the last decade. In the meantime, we have evaluated most of these in detail, taking a closer look at both energy consumption and indoor comfort, as well as the interaction between buildings and users. This magazine presents an overview of the lessons learnt from the projects. The evaluations show that it is indeed possible to build ‘tomorrow’s houses’ today, i.e. carbon-neutral buildings whose envelopes harness the sun for the sake of people can be designed and built using readily available technologies, products and processes.

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