Passive
Solar Designs
The first thing you
notice about a passive solar house is that it’s easy to tell which
side of the house you’re looking out, whether the sun is out or
not. There are lots of windows on the south side, which opens up to
the outside world to maximize exposure to the sun, while the north
side has just a few, smaller windows to keep the winter cold
outside. An awareness of the site the house occupies is a part of
its basic design. Compare this to a conventional house, where it’s
almost impossible to tell which side of the house faces
south—unless the sun is out. These houses are indifferent to the
site they inhabit, which means they require more resources to
maintain have to work harder to maintain indoor comfort
levels.
Passive solar design helps us limit a home's lifetime impact on the
local ecology and minimize heating and cooling costs. By designing
with a keen awareness of the sun's path and the local climate we
are able to improve the quality of natural daylight inside the
house and greatly reduce the external energy inputs needed to
maintain a comfortable indoor temperature year round. That means
much less oil or gas coming out of the ground or less wood coming
out of the forest. Passive solar design has four main components:
solar orientation, glazing to floor area ratios, insulation and
thermal mass. Each is essential, and the four work together.
Passive solar homes are also much more comfortable for the people
living inside than conventional buildings are. Solar heat feels
better than any other kind on the human body. And solar heat stored
in the abundant thermal mass of our floor system means that the
indoor temperature remains relatively constant during both daily
cycles of day/night and longer seasonal cycles. A passive solar
home tends to stay warm in winter and cool in summer, without
expensive mechanical heating systems.
Orienting a building's
longer side to within ten degrees of solar south allows us to take
full advantage of the sun's light and heat. Sizing and positioning
the windows on each side of the house according to careful
calculations maximizes heat gain and minimizes overnight heat
loss--the most important factors in our cold northern climate.
Adequate thermal mass properly positioned to absorb the sun's heat
allows us to store it during the day and then slowly release it
once the sun goes down. Earthen floors are great for this. Finally,
abundant insulation in the walls and ceiling, and double-paned
windows ensure that most of the heat gained during the day will
stay inside the building. For our walls and ceilings, we combine
the timber frame structure with a lightweight truss system that
allows us to achieve R-38 for the walls and R-60 for the ceiling,
while all but eliminating thermal breaks.
