Lately, the concept of passive house design has come to prominence in building and design discussions. A passive house is designed to require minimum energy input for heating and cooling. While some of the techniques used are modern, such as geothermal heat pumps and heat recovery ventilators, many of the techniques have a long history in building design. Here are a few of these well-used techniques and where best to apply them.
Consider Your Shape Factor
The shape factor is merely a fancy name for the surface-to-volume ratio of a house. A house loses or absorbs heat through its exterior surface, while the volume determines how much livable space is available inside. Therefore, a low shape factor means a home will have less need for heating or cooling. Within practical building shapes, a building that is approximately cubical will give you the greatest interior space for a given exterior surface area. Thus, in general, a more rectangular two story home will be more efficient than a rambling ranch home. As a bonus, this type of home will use less building material and therefore be more economical to build as well.
Plan Your Windows Wisely
While windows have made great strides in efficiency and design lately, they are still very poor insulators compared to the walls in which they are mounted. A good modern window has the equivalent of an R-value of about 4, while an exceptional modern window might increase this to an R-value of about 6. While this is far superior to average windows from even a decade ago, these windows only provide at most a third to half the insulation of a log wall, without the benefits of thermal mass. For the most efficient and passive home, use high-quality windows but avoid large banks of windows like those sometimes found on cathedral ceiling room walls.
Use Trees to Your Advantage
One way to get around some of the issues of building a passive home is to use Mother Nature to provide the solution for you. If you plant deciduous trees on your southern exposure, the leaves will keep the walls and roof cool in the summer. Once the leaves fall in the cooler months, the bare tree will allow the sun to heat the building in the winter. If you have cold northern winds in the winter, then evergreen trees planted on the northern exposure will also help to keep the winds down.
These are only a few ways to build a home with passive means for lower energy consumption. If you are interested in building an energy-efficient log home of your own, please contact Real Log Homes today.