What does light mean for architecture?
Sunlight is existential. Without it, none of us – people, animals, and plants – would exist. But we humans can’t bear all the light emitted by the sun. That’s one reason why we build houses: to protect us from rain, cold, and sunlight. And we use windows to regulate how much light we let in, so it’s enough but not too much.
How much light do we need inside a building?
I like generous window openings in houses. But we need less light than we think: one tenth of the floor space of a room is the statutory minimum for windows in residential buildings. In an art gallery, one half to one percent of the light outside under the open sky provides sufficient natural lighting for the artworks inside.
You received the prestigious Daylight Award for the Kirchner Museum in Davos. What were the challenges?
We wanted to show the art of Ernst Ludwig Kirchner in Davos, in the Alps, using natural light. This led us to a brand new skylight solution. Davos’s rooftops are covered in snow for three months of the year. Even a thin layer blocks out all the light. That’s why daylight enters the museum only through side windows into a skylight space, which is separated from the exhibition rooms below by a glass ceiling. The windows of the skylight room and the ceilings are etched to diffuse the light through the rooms without casting shadows. To ensure the walls of the exhibition space are lit equally even in direct sunlight, the side windows in the skylight spaces also have blinds. These are adjusted automatically during the day and over the course of the year to the angle of the sun. We kept the design of the exhibition rooms simple to keep the focus on and show Kirchner’s works to their best advantage. The Kirchner Museum was one of the first museums to pursue this line of thinking. Although the museum first opened in 1992, it still impressed the jury of the Daylight Award in 2012 – a full twenty years later.
What advantages does daylight have over artificial light?
Daylight contains all the colors of the spectrum, but it changes throughout the day and depends on the weather. Nevertheless, we prefer to work with daylight whenever possible – even for art museums. It’s the best kind of light to reflect the colors in artworks. If we as humans spend a long time in rooms lit purely by artificial light, we really spring back to life in daylight. Seeing outside is also important. It’s one reason why our museum designs always feature a space with windows after two or three closed-in exhibition rooms, to let people gaze into the distance.
What is important when lighting a building?
Its use, location and thus its view are all-important: If the building looks onto a lake or a park, large windows make much more sense than if it has a view of a car park. Take the Prime Tower high-rise office building, for example: it has the city of Zurich spread out at its feet, not to mention busy roads and a maze of railway tracks. We had the façade made entirely of glass and dispensed with closed balconies, so that workspaces two or three rows back – and not just those by the windows – also have an expansive view of the city. It also depends on how a building is used. People don’t want to feel like they’re on display in their own homes. If it’s an office, criteria such as sufficient lighting and glare-free workspaces take priority. In art studios and tradesmen’s workshops, for instance, light from the north is often preferred, as it provides more even and constant lighting conditions.
What impact does artificial light have on us humans?
Artificial light was very liberating for humans. It freed us from dependence on daylight, allowing us to work at night and to stretch out our free time into the evening hours. It’s interesting to note that lighting with the bluish tones of daylight appears cold and artificial to us in the evenings. At that time of day we prefer a warmer light.
LED is all the rage now. Does this technology herald a revolution in artificial lighting?
We’ll have to wait and see. Fluorescent lamps, used everywhere in offices and stores, have been five times more energy-efficient than normal light bulbs for decades. LED lights have only recently become slightly more efficient than fluorescent lamps. So it makes sense in energy terms to replace light bulbs with LED lamps, but not yet to replace existing fluorescent lamps with LEDs. However, the advantage of LED is that slimmer, longer-lasting lights can be produced, opening up new design opportunities.
Apartments, museums, Switzerland’s tallest building: your firm Gigon / Guyer has some impressive achievements. Do you have any dreams left?
Naturally! We dream of commissions to build libraries, schools and more museums, as well as new apartments and offices. And we’re not even all that fussy about the type of building. It’s much more important for us to establish a sound relationship based on trust with the property developers. You see, building is a bit like climbing a mountain together. There’s a lot to get right – not just the architecture, costs and deadlines. At the end of the day, the people who bring a building to life should feel at home in it. That’s our ultimate objective.