Vernacular construction technologies are based on centuries of practical wisdom, refined through countless trials and errors. This process eliminates all irrelevant aspects, creating highly efficient and simple systems that are intrinsically adapted to the local climate and resources. These methods demonstrate how to conserve heat with minimal energy, offering valuable insights for modern buildings, promoting energy efficiency, and environmental harmony. In this article, we have already covered traditional passive cooling techniques, such as Persian wind towers and Arab mashrabiya. Now, we turn our focus to strategies applicable to cold climates, exploring effective solutions for heat retention and space heating.
In cold climates, passive construction approaches differ significantly from those used in hot regions. Instead of prioritizing abundant ventilation and cooling mechanisms, strategies are adopted that favor thermal energy retention, such as the use of high thermal mass materials, the creation of a greenhouse effect, and minimizing heat loss. Thermal inertia, for example, is especially recommended in places with large temperature variations, as materials like stone or concrete absorb heat during the day and release it gradually at night, stabilizing the internal temperature. Greenhouses act as natural solar collectors, capturing and storing solar energy in enclosed spaces, which can be used to passively heat adjacent areas, in addition to providing ideal conditions for plant growth and thermal comfort in harsh climates. Subterranean constructions utilize the thermal stability of the ground to ensure comfort both in summer and winter. When combined with passive solar design, these solutions significantly reduce the need for mechanical heating and cooling systems, promoting more sustainable and energy-efficient architecture.
A prime example that comes to mind is the igloo: dome-shaped shelters traditionally built by the Inuit people using compacted snow blocks. Despite being made of frozen water, the air trapped in the snow acts as a barrier to heat loss, allowing the internal temperature to remain well above freezing, even in extremely cold outdoor environments. Built in a catenary shape, similar to a paraboloid, igloos optimize structural integrity by distributing the snow load as compressive forces, reducing the risk of collapse. The snow blocks, initially cut into four-sided shapes, are reshaped to improve interlocking, resembling Inca architectural techniques, and over time, they compress and shorten due to the natural sliding of the snow.
In high-altitude regions like Tibet, thick stone walls, more than a meter wide at the base, are used to absorb and release heat slowly, creating insulation and stability. These walls taper as they rise and are designed to withstand intense cold as well as earthquakes. Materials such as granite, slate, and wood are used in construction, with roofs sealed with mud or clay and additional insulation made with straw and stone rubble, providing flexibility and protection.
In desert regions, adobe structures excel at regulating temperature due to their ability to efficiently use thermal inertia. Thick adobe walls absorb the intense heat of the sun during the day, storing this energy in materials like clay and mud. This natural process eliminates the need for artificial heating or cooling systems, providing a comfortable environment in extreme climates while reducing energy consumption from forced heating systems. Additionally, adobe is a local and sustainable material, reinforcing its relevance in ecological and traditional construction practices, especially in regions where the temperature variation between day and night is significant.
Scandinavian wooden houses use interlocked log walls to create a natural barrier against the cold, minimizing drafts and retaining heat efficiently. They become naturally energy-efficient due to the unique thermal properties of wood, with its natural thermal mass, meaning it can absorb, store, and slowly release heat, helping regulate indoor temperatures. The interlocked structure of wooden walls also reduces drafts, ensuring better insulation and minimizing energy loss. Additionally, wood’s ability to "breathe" helps control humidity levels, further enhancing indoor comfort.
Meanwhile, subterranean dwellings, such as Chinese yaodongs and Berber houses, take advantage of the natural insulation properties of the earth. By being built partially or completely below ground level, these constructions maintain more stable indoor temperatures, protecting occupants from extreme surface temperature fluctuations. In winter, the surrounding earth acts as a thermal insulator, retaining heat and keeping interiors warm. In summer, the lower temperature of the ground helps cool the internal environment, creating a comfortable and cool space even in hot climates. This type of construction efficiently utilizes natural resources, reducing the need for mechanical heating and cooling systems, and promoting a more sustainable and economical approach to thermal comfort.
Drawing on these ancient techniques and combining passive solutions with simple modern technologies, another interesting, low-tech, and highly inventive strategy is the Trombe wall, developed in the 1960s by French engineer Félix Trombe and architect Jacques Michel. It consists of a thick wall with high thermal mass—usually made of concrete, stone, or adobe—placed on the sun-facing side of a building, with a layer of glass installed a few centimeters in front of it. During the day, sunlight passes through the glass and heats the wall, which slowly absorbs and stores the heat. As the temperature drops at night, the wall radiates the stored heat into the internal space, maintaining a comfortable temperature without the need for mechanical heating. Small openings at the top and bottom of the wall can also be added to allow warm air to circulate naturally. Trombe walls are particularly effective in climates with significant daytime and nighttime temperature fluctuations and are a popular feature in passive solar architecture, providing an energy-efficient solution for regulating indoor temperatures.
These traditional techniques, grounded in thermal mass and passive solar heating, offer sustainable solutions that, when integrated into contemporary architecture, reinforce the connection between buildings and the environment, preserving cultural heritage and promoting long-term sustainability.
