What is a Passive House?
Over the last century professionals have been evaluating and refining construction practices throughout the world. The Passive House standard is the distilled result of all those years of trial and error. Based on modern building science and years of data collection from the field Passive House U.S. has established a standard of building performance that is the bleeding edge of energy efficiency and building durability.
A Passive House is up to 90% more energy efficient than conventional homes and thus, far cheaper to maintain.
A Passive House is up to 90% more energy efficient than conventional homes and thus, far cheaper to maintain.
The five principles of the Passive House
- Envelope. A continuous layer of insulation wraps the whole structure; under it, around the walls and up the roof. This insulation eliminates cold spots that bleed energy and provide potential for mold growth and condensation. More than 90% of moisture problems in a home come from air leakage. A Passive House is air tested to at least .6 air changes per hour! What that means is that if you combine all the cracks, holes and penetrations where air could move into or out of a structure you end up with the equivalent of a 2-3 inch hole. ... in your entire building. Under the same testing conditions a standard house would have a leakage area equal to a large window being open all the time.
- Balanced continuous ventilation. All Passive homes have Heat recovery or Energy recovery ventilators. These units continuously exhaust your inside air, while capturing up to 90% of its heat and transferring that heat to fresh outside air.
- Efficient mechanicals. All mechanical systems in the structure must be sized appropriately and be energy efficient. Because of the air tight and insulated nature of the building heating and cooling systems can be sized much smaller than what would be installed in a standard or energy star structure. High efficiency light and appliances are used throughout.
- Passive elements. The building is oriented and designed to take advantage of passive heating and cooling conditions from the surrounding environment. South facing windows, materials with high thermal mass, the ability to pull or push heat to or from the ground through a mechanical element, taking advantage of natural shading for climates that require cooling are some of the examples.
- In an age where there is so much anxiety over the warming environment the Passive House standard creates a home that generates far less carbon than any other standard of construction. Because of how efficient these buildings are the addition of renewable energy collection can quickly move a Passive House from being a consumer of energy, to being a producer of energy!
In the above thermal image you can see that the outisde of the passive house walls are as cold as the tree, whereas the passive house windows are losing as much heat as the standard construction walls are on the left hand side of the picture.
