Objectives: Use the classical Chalet model to design a primer for homes in the Swiss Alps, with the biggest concern being temperature maintenance. During the harsh winter season in Alpine climates, methods of sunlight absorption and insulation are very important passive heating strategies
Strategies to be employed by the primer: thermal mass and temperature-conscious materials, orientation of the buildings in relation to topography and the sun, and stilts/ elevated ground plane as a design strategy. These strategies combined in the primer comprise the passive heating strategies that make best use of the environment while maintaining a livable indoor space.
Strategy 1: Putting the house on wooden stilts
In the summertime, stilts allow for the warm air in the valley to convectively flow underneath the house at night, creating a residual warmth from the daytime as well as ventilation. This ventilation prevents rotting on the wood, and the stone disks separating the pillars from the base of the home also help to ease the risk of rotting on the most important structural members. Air flow during the summer creates a comfortable environment during the day and at night, based on the mountain’s climate and wind flows.
During the winter, stilts become even more important. Snow in the alps remains frozen during the winter because of the dry air, and doesn’t tend to melt and re-freeze as it does in more humid climates. Because of this, snow becomes a good insulator for the house during the wintertime. The snow piles up beneath the house, and prevents radiant heat loss from the house’s interior to the frozen ground beneath the snow. In regards to functionality, stilts allow the house to be entered and exited from in the presence of snow.
Strategy 2: Orientation
Orienting the houses southward is very important in relation to the sun, and having one of the roof flanks facing uphill towards the mountain is also very important. Modern passive heating strategies include glass glazing with double-panes and insulation, letting in maximum daylight on the southern side of the building during all times of year. During the summertime, the low-hanging roof gables block direct overhead sunlight that would cause an unpleasant rise in the indoor temperature. The valley-facing side of the house is open to ventilation (convective heat flow from the valley) at night.
During the wintertime, orientation is also important. The glass windows to the south still let in a ton of light, but the low gables don’t block direct overhead sunlight as the sun’s path changes in the colder months. In the winter, the deepset windows on the east and west facing sides of the house will receive even more warmth from the reflected sunlight off of the snow. The frigid night wind from the top of the mountainside is offset by the roof’s orientation, the roofline and snow pile up to create a sort of insulating barrier from the home’s interior.
Strategy 3: Materiality for thermal mass and insulation
During the wintertime, heat retention is the biggest concern in the Alps. Insulation can be achieved by taking advantage of the snow that falls, having the roof’s pitch not quite steep enough to drop off all of the snow that piles up. The dark wooden material of the home itself absorbs sunlight during the day and has low conductivity, meaning that it loses heat slowly to its surrounding environment and retains heat longer through the night than a steel structure would.
During the summer, the temperature in the Alps is nice during the daytime but plummets at night. Having thermal massing to absorb the sun’s heat during the day offsets the uncomfortable cold of the nighttime. The roofs are a dark wooden structure, with giant slate tiles on top. The slate absorbs and retains heat for a long time, radiantly warming the interior of the home by transferring heat throughout the night. The heat obtained from the roof is kept well inside the tight wooden frame of the house at night, and as it slowly warms up during the hottest hours of the day, it serves to keep the home shaded and cool.