We’re SuRe…sustainable and resilient. For us, sustainability is mostly about energy: how much we use and how we make it. That’s why we’re striving to meet the most stringent energy efficiency building metric in the world – the Passive House standard (PHS).
In building parlance, “passive” is often short for “passive solar” and most often refers to a building that is at least partially heated by the sun. However, in the PHS a Passive House is a building that has been designed from its inception to reduce heating and cooling energy demand to the point that conventional HVAC systems are unnecessary. This standard, created in Germany in the 1980s, has been growing in popularity in the United States over the past decade and has been shown to reduce home energy use by up to 90%. The PHS is conceptually simple, having only three performance requirements:
Annual Specific Heating/Cooling Demand < 15 kilowatt-hours per square meter
Annual Primary Energy Use < 120 kilowatt-hours per square meter
Air Tightness of Building Envelope
0.6 air changes per hour @ 50 pascals of pressure
Simple but not easy. Reaching these benchmarks requires a building with an exceptionally efficient envelope, the part of the building designed to thermally separate the small volume of inside air from the huge volume of outside air (also called Nature). The Passive House community employs 6 main strategies to meet these goals:
* Super-Insulate – keep the outside, outside
* Airtight Construction – seal up your seams to keep conditioned air in
* Minimize Thermal Bridging – keep insulation continuous to prevent heat sinks
* Energy Recovery Ventilation – bring fresh air in and capture energy of exhausted air
* Use the Sun – let in the sun for winter heating
* Control the Sun – block the sun for summer cooling
The attention to detail required to pull this off is a formidable task. Add in the complexity of creating a flood-proof building and suddenly a small 1,000 square-foot home becomes a very complicated project, but one that we feel is the next step for coastal housing. Over the next couple of weeks, we’ll go into greater detail about each of these strategies as we are applying them in the SURE HOUSE.