Is your home passive? By that, I don't mean "does your home lie there like a bump on a log"! The passive home movement, which originated in Europe, is crossing over to US shores in a big way, and it's changing the way we think about energy conservation in the home. Get excited, because the way you save and use energy might be about to change, especially if you're thinking about buying or building a new home, which provides a great opportunity to get in on the ground level with passive homes.
This concept originated in Germany, and it's actually not limited to homes. Businesses and institutions can use passive building techniques too. The idea behind passive structures is that instead of using energy to heat or cool the structure, the structure itself should work to maintain its own temperature. A variety of techniques and building materials are involved in the construction process to make this work.
In fact, the whole house relies on passive means to save energy and increase efficiency, rather than active ones. That's what sets it apart from other forms of energy-efficient and environmentally-friendly homes, which often use various technologies and equipment to achieve high energy ratings.
One thing that distinguishes passive homes from their counterparts is their low air leakage. This helps prevent the escape of warm air in the winter and cool air in the summer. They're also extremely well insulated (that includes walls, windows, floors, and roofs) to maintain a stable core temperature. Occupants of a passive house may use up to 5 kWh per square foot for heating and cooling according to the building standard used in Germany, but they don't have to.
And in fact, when the house is well-designed, they don't need to. The temperature shouldn't fluctuate considerably, and the minimized leakage of air keeps humidity levels stable as well. The end result is a home that can be slightly cooler in the winter or warmer in the summer than is conventional, but one that uses far less energy than its neighbors. There's also much less waste: thermal imaging studies of passive houses versus conventional ones illustrate how great they are at conserving heat in the winter and keeping heat out in the summer.
Heat exchangers built into the home provide a steady source of heat and temperature control in addition to air circulation, and they're driven by the flow of warm air itself, without need for an external system. These homes can also be designed with solar collectors, solar water heaters, environmentally-friendly landscaping, and other low-energy, low-impact design measures. Typically a passive house is built from post-consumer materals and meticulous care goes into the design and placement of the home along with what it's built from to achieve a minimal environmental footprint.
While the passive house movement comes from Europe, a lot of the building techniques it uses are actually from North America, adapted to the climates of regions like Scandinavia. It's possible to build passive houses in a variety of extreme climates; a Phoenix construction firm can build a home for the desert climate just as easily as a team in Minnesota can develop a home ready for harsh winters.
Check out this example of a beautiful passive home in Menlo Park, California to see how this building technique can shine under the hands of a dedicated architect and design team. This project would have required a cooperative effort from a variety of green building experts, from people familiar with passive HVAC needs to landscapers ready to work on establishing a garden that would complement the home.
