Chapter 2: Passive Design
by Mark Turner, CEO, GreenSpur, Inc.
Digital rendering of side elevation. | View PDF
Solar panels and bamboo floors maybe the poster children of green building, but its the passive design strategies the can offer the greatest improvements of performance and return on your wallet. Growing up my father used to take our family camping a lot - we were the Griswolds of the woods. And like Clark, my father had no limits to the crazy conditions he would expose us to particular in the harsh conditions of western Wyoming. In the winter he would tell us to put the tents in the open to gain solar heat during the day; in the summer he would instruct us to put our tents in the shade and position them so the door was exposed to the morning sun.
He would tell us to line the fire with big rocks so the heat would retain itself. And when it came to weather he emphasized the importance of layers and keeping the core dry, insulated, and protected from the wind. And while its not a perfect comparison, both camping and passive solar design works closely with what nature provides us: insulation, shading, orientation, and heat mass.
Angles of the sun, to maximize energy efficiency, is important. This diagram shows the angle of the sun during the Summer solstice. | View PDF
In McLean, we have chosen a building envelope made from SIP's (Structurally Insulated Panels) which offer some of the highest R-value and insulation performance criteria in the industry. We have incorporated two foot roof eaves, architectural trellises, Lo E window coatings, and built around existing old growth trees to shade the heat gains from the sun. We have orientated the building considering the summer and winter solstice — shading the windows from the high summer sun and allowing heat gain for the lower winter sun. Finally, we have carefully modeled our massing both in terms of the overall size of our southern building facade and through the use of concrete slabs and warmboard sub-floor on the inside which will retain the heat for longer periods of time. Even though we won't start construction for another week or two, this building has been built dozens of times on 3D energy modeling software — carefully considering our passive variables — which in the end has saved us over 51% on our overall energy consumption. Passive solar design makes some of the most economical and sustainable sense in green building. Next time your camping give it a try.
