Insulation is also a big, big deal. Joe Lstiburek said to the audience in the opening plenary, “insulating good, solar bad,” referring not only to failed passive solar homes but the over-reliance on slapping technology on a roof and calling it a green building. His method of choice has been foam but more earth friendly, energy sipping products were on display. Cork Insulation has found its way across the Atlantic and while it comes at a premium price, it is a uniquely healthy choice. More mainstream was German made Agepan fiberboards which clad buildings in an air tight water resistant coat that is still vapor open to reduce chances for rot.
For a stateside low impact insulation which performs even better when it comes to rot prevention, look no further than Roxul DrainBoard, a dense board made from mineral wool – a compressed mixture of rock and slag. Priced similarly to XPS foam but without the environmental impact, DrainBoard is vapor open and can be used underground.
The most exciting aspect of future high performance homes may be the recent innovation of Phase Change BioPCmat, a bio based waxy material in a plastic blister pack which when placed inside a wall can retain and release heat at prescribed values. As the wax melts at say 78 degrees it can store the equivalent heat as 12 inches of concrete in just half an inch. By absorbing heat in the day and releasing it at night buildings can use much smaller HVAC equipment, thereby saving money and energy while keeping interiors comfortable. It doesn’t get more passive than that.
Lead Photo VolksHouse by Mosa