The San Francisco Bay Area is rich with examples of Green Architecture, and is arguably on the forefront of the green building movement. Many people here have heard of the Passive House Standard, but not many really know what it is or how it works.
In essence the term “passive house” represents the idea that these houses do not need to rely on large, conventional heating systems that require lots of energy to provide heat. Instead they passively recycle the free heat generated from sunlight and activities within the home, and are supplemented by smaller heating systems that require far less energy to run. Turning lights on, running the refrigerator, cooking, using a computer, and the people provide a constant source of free heat. This heat is contained inside the building envelope and is recycled by transferring it from outgoing stale air to incoming fresh air through a heat recovery ventilator. The houses are so well insulated and air-tight, that warm air does not escape through the building envelope and cold air isn’t allowed to creep in.
If you compare a Passive House with a conventional home, a Passive House is up to 80% more energy efficiennt, indoor air quality is superior, and the buildings themselves are more comfortable to live in since the temperature does not fluctuate.
It is critical that we start applying t he Passive House concept before relying on alternative energy sources such as solar or wind energy. Think of it this way: only using solar power as a remedy against energy waste is similar to resolving the problem of a leaky gas tank by ignoring the leak and filling up with biofuel instead of gasoline. It might make us feel better, but it doesn’t change the fact that our gas tanks are leaking and energy is being waster. They help, but ignore the core problem, which is our buildings are energy hogs.
Here in the Bay Area, where our climate is relatively mild, it is one of the easiest places to reach Passive House standards. We have no excuse for building structures that waste heat and require us to turn on our heaters. In summer, we can turn off the heat-recovery ventilator and throw open the windows and doors to enjoy the nice weather. In winter, the mechanical heat-recovery ventilator can be used to allow the building to “breathe” without wasting energy. Fresh, filtered air is circulated 24 hours a day, resulting in better indoor air quality and energy efficiency.
Buildings are responsible for 40% of all energy consumed and Green House Gas emissions. Clearly, the building sector needs to reverse this trend to avoid the possible catastrophic consequences of climate change. The best way to achieve this is through energy efficiency. The Passive House Standard has been tested throughout Europe over the last 15 years and is a proven strategy. Researching this standard and adapting this know-how and experience to our building industry is the fastest path to designing and building projects that perform to higher standards of energy efficiency, comfort and improved indoor air quality.
Nabih Tahan, AIA, MRAI is a licensed architect who returned to Berkeley from Austria to remodel his home while demonstrating sustainable design and construction techniques being used in Europe. He is the founder and a principal of BauTechnologies.