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September 25, 2014
Passive House design and building concepts have gained significant popularity worldwide over the past several years with more than 50,000 residential and non-residential units in existence, according to the International Passive House Association.
Now, the concept has begun to establish momentum here in the Northwest with a number of local developers and builders successfully using those strategies in both certified and non-certified Passive House buildings.
The Passive House concept represents today’s highest energy standard with the goal of reducing heating energy consumption of buildings by up to 90 percent. A building constructed using passive house principles is very well-insulated and virtually air-tight, with high-performance triple-glazed windows and a strategic limitation of thermal bridging, which often allows heat to leak through walls. It is primarily heated using passive solar gain, and internal gains from people and electrical equipment, such as a condensing clothes dryer.
With energy losses minimized, remaining heat demand can be met using a very small source, such as a ductless mini-split heat pump. A heat recovery ventilator is used to provide a constant, balanced fresh air supply, which offers occupants terrific indoor air quality filtered from external pollutants, dust and pollen.
The “passive” in Passive House describes the buildings’ ability to rely on natural resources through the capture of free solar energy instead of an active system, such as a furnace. Design and construction of Passive House buildings yield a net savings based on lower energy bills and longer lasting material use, particularly windows and insulation.
The most notable Passive House locally is Park Passive, built by Seattle green builder Cascade Built. Now one year old, Park Passive was the recipient of significant national media attention, including the acclaimed AIA National Housing Award for demonstrating that great design, executed by our firm, and sustainability can co-exist.
Park Passive’s owners suggest that building to such rigorous standards increased the construction cost by an average of 5 percent, while they now enjoy energy bills that are dramatically less than their previous home.
Cascade Built is also finalizing a townhouse project on Capitol Hill with units designed to meet Passive House standards, and one unit is expected to meet the difficult certification.
Dwell Development’s Cork House, part of a multi-home development in Columbia City, was designed and built to Passive House standards. With completion slated for later this year, the company also added a passive house consultant to its team. Another builder contributing to Seattle’s Passive House landscape is Portland-based Hammer & Hand. The builder/developer has two non-certified Passive House projects under its belt, including one under construction in Seattle’s Madrona neighborhood.
This movement into uber green building and design, and our new understanding of Passive House, is creating an exciting time for designers and builders alike. Alongside certified Passive House projects, we also see an opportunity for the application of Passive House techniques and high-performance products to every home and building as a way to maximize energy independence and reduce total cost of ownership through lower utility bills and maintenance costs.
Key Passive House strategies include capturing passive solar energy to heat the home, the creation of an airtight envelope using dense packed insulation in exterior walls and ceilings, insulation of the floor plate, high performance windows and doors, and a heat-recovery ventilator for continuous fresh air.
While we are just seeing the beginning of a Passive House movement in the Northwest, we expect it to quickly take hold.
Next year, NK Architects will break ground on a Passive House-certified apartment project a first in the state of Washington. Residents will enjoy the same benefits of those individuals living in Passive House single-family homes: significantly reduced energy bills, a temperate indoor air temperature, notable fresh air and quiet (a side benefit resulting from the additional buffer of outside noise and lack of internal noise that typically comes from ducted heating systems).
Although there are many positives, Passive House doesn’t come without its challenges. Top barriers to adoption continue to be an industry that needs to better understand building science and solutions that are already available to increase energy independence; a wider understanding in the marketplace of the role that buildings play in addressing our growing carbon footprint; and industry resistance to change because they know what they’ve already done.
For architects, builders and developers, Passive House’s compelling messages promise zero-energy ready properties that protect owners from energy cost inflation, differentiate the product in a robust marketplace, and provide an unparalleled level of comfort for inhabitants.
Passive House strategies are simple in theory and we believe simple enough to become part of Seattle’s mainstream building standards. As a firm, we have created a dedicated initiative to engage with developers and builders to educate them on Passive House strategies that enable our future buildings to target net-zero energy use. As my daughter recently told me, “it’s just a matter of time before FOMO (fear of missing out) takes hold.”
Joe Giampietro is managing associate and Certified Passive House Consultant at NK Architects in Seattle. He has 30 years of experience in real estate development, land-use planning and architecture.