The Passive House could save energy, stop climate change
December 12th, 2008 by Jim JustThe passive house could play a major role in cutting energy consumption and stopping global warming. All it would take is radically altering our building practices.
A Passive House is a very well-insulated, virtually air-tight building that is primarily heated by passive solar gain and by internal gains from people, electrical equipment, etc. Energy losses are minimized. Any remaining heat demand is provided by an extremely small source. Avoidance of heat gain through shading and window orientation also helps to limit any cooling load, which is similarly minimized. An energy recovery ventilator provides a constant, balanced fresh air supply. The result is an impressive system that not only saves up to 90% of space heating costs while also providing excellent indoor air quality.
To be called a “passive house,” a building must meet the passive house performance standards which are set by the Passive House Institute in Germany. The basic standard is that a building must consume no more than 15 kilowatt-hours per square meter in heating energy per year (equivalent to 4746 BTU per square foot per year). This is achieved by constructing a building envelope, (floors, walls, ceilings, and a roof) that is extremely well insulated and air tight. This means R40 in the walls and R60 in the roof and floor. The building must not leak more air than 0.6 times the house volume per hour at 50 pascals of pressure. The result is a building that uses 90% less heating and air conditioning energy than a typical building according to the Passive House Institute US.
If all new houses were to be passive and existing homes were fully retrofitted to the passive house standards, we would be far along the road to stabilizing our climate.
Buildings are responsible for almost half of U.S. energy consumption.
