Bioclimatic Design


Bioclimatic Design is a design process that takes into account cli­mate and envi­ro­men­tal con­di­tions when designing for optimum comfort for users with minimum outside energy use reducing building’s environmental footprint. It deals with site and building design using archi­tec­tural ele­ments and techniques that will minimize depen­dence on mechan­i­cal sys­tems. Bioclimatic design was used successfully throughout ages in vernacular architecture. Examples:

  1. Thick walls with substantial thermal mass keep the building cooler in the summer, warmer in the winter
  2. Buildings are oriented so winter sun can heat them; summer sun shielded off by substantial overhangs
  3. The use of high open atrium/chimney type structure in the middle of the building in hot climates causing natural air movement pulling air from the outside through shaded, cool rooms
  4. Deep porches of the South surrounding the building, shading multiple windows located on all sides for easy cross ventilation

The bio­cli­matic building doesn’t require instal­la­tion of additional com­pli­cated and expen­sive sys­tems, but uses specific archi­tec­tural ele­ments to increase the ener­gy per­for­mance and provide nat­ural com­fort to occupants.

The main considerations of Bioclimatic Design are:

  1. The study of natural elements of the site: topography, geology, air, sun and wind and vegetation including the specific microclimate of the site to determine optimal position of the building.
  2. Consideration of complexity of form vs. building compactness and its impact on energy use; i.e. compact shape in cold climate and maximizing exterior wall area to encourage natural cooling breezes in hot and humid climate.
  3. Use of correct landscaping features and planting to minimize water use, provide shading, windbreak
  4. Designing building form to optimize natural ventilation.
  5. The use of breathable exterior wall system using breathable exterior wall finish, breathable house wrap, natural insulation and mineral-based interior paints to create synergistic effect that passively regulates interior climate.
  6. Selection of colors of exterior finishes to either reflect or accumulate heat, depending on climate; interior colors will influence the amount of artificial light required to light up a room.
  7. Solar access analysis to determine building solar orientation resulting in:
  • concentration of utility/support uses (pantry, garage, storage) on climatically most challenging side (west in hot climate, north in cold climate)
  • selection of cor­rect fen­es­tra­tion type and solar shad­ing to maximize daylighting and at the same time minimize electric loads, provide solar heat in the winter without excessive solar heat gain in the summer
  • use of ther­mal mass of solid walls and or/ floors to minimize thermal fluctuations

Next time we will look closer at bioclimatic design in hot humid climate with mild winters.

History and Lifecycle Musings

When visiting Rome, I was completely awestruck by the 2000 year old concrete dome of the Pantheon. I stood there with my jaw dropped: “What a life cycle value!”, wondering why our modern concrete with all the super technology and equipment cannot often last even one generation. I have a deep respect for the wisdom and skills of classical and vernacular designers, and as a designer today, I often draw from it; however I am not completely convinced that our modern day buildings need to last a very long time.  After all, only some of the old buildings survived this long; most did not. Will any of the buildings of our era last even a few hundred years? Do they have to?

Our society and lifestyles change quickly. New, exciting and easier to live with materials come up every day. Everything around us changes with lightning speed. And so our buildings will have to change with us. What is crucial however, is that we do not waste the materials, but reuse - and LEED recognizes that, and not only that; it is about the whole building design, where all systems and design decisions come to play together. It definitely is not perfect; it is a fairly new system but is a good start.

It would be nice to leave our architectural footprint that will tell the story of our times to future generations, but at the same time, we have to be very frugal with material resources and tread gently on the environment with our 21st century lifestyle.