The term Passive House is a translation from the German Passivhaus and refers to a construction concept. A building constructed according to rigorous Passive House standards is super insulated, highly energy efficient, comfortable and durable. An airy 70 to 74 degrees is maintained year round without the need for conventional heating or air conditioning. Many Passive Houses are fitted with advanced smart technology to further increase energy efficiency, particularly to control lighting, heating and cooling.
THE FIRST PASSIVE HOUSE IN THE USA
Katrin Klingenberg, who studied architecture in her native Germany, introduced the Passive House principles to the US in 2002 by building her own Passive House residence in Urbana, Illinois. Karen has dedicated her career to designing homes and buildings that lesson the impact on our climate. She co founded PHIUS (Passive House Institute US), an organization that is “committed to making high-performance passive building principles the mainstream best building practice, and the mainstream market energy performance standard.” The organization has trained more than 1,700 architects, engineers, energy consultants, energy raters, and builders. It also is the leading certifier of passive buildings, with more than 120 single and multifamily projects certified and more than that in the pipeline.
CAN ONE SET OF STANDARDS WORK ANYWHERE?
The Passive House Institute (PHI) in Germany claims that one set of standards can be applied to any situation in the world and achieve the same results. In Europe, where there is limited climate variety, this may be feasible. In fact, the regions of the US where the Passive House movement has had the most success have moderate climates very similar to central Europe. There have been far fewer Passive Houses built in in areas that experience more extreme temperatures.
CLIMATE SPECIFIC STANDARDS FOR THE USA
PHIUS maintains that one size cannot fit all and that the Passive House standard should change appropriately according to the climate. There are also other factors such as differences in culture, energy costs, technology and availability of materials that should be taken into consideration. This difference of opinion with PHI caused such a rift that the two organizations had a serious falling out and severed ties in 2012.
This was a serious setback for the green movement and caused widespread insecurity among professionals, manufacturers, lawmakers and clients. Negative exposure was the last thing the organization needed, particularly when so few people knew anything about the program.
THE NEW STANDARDS
With no longer any reliance on PHI, PHIUS has forged ahead with its own certification programs that combine a thorough Passive House design verification protocol with stringent quality control measures. Their current standards were developed over three years under a US Dept. of Energy Building America Grant. They take into account a full range of variables including climate zone, energy source and cost and hope to make the model more appealing to the American market. PHIUS certifiers review every aspect of a Passive House from design through to on site testing and completion. The final project receives a RESNET HERS index score. This is the industry standard by which a home’s energy consumption and efficiency is measured.
The cost of building a Passive House is about 10% higher than regular construction since windows, walls and doors need to have outstanding insulation. However Passive House heating systems cost less and they require an average of 90% less energy to operate. Each project is different but when the one time construction cost is amortized over the life of a mortgage, Passive House owners should expect to save money every year.
The original PHI standards that evolved from the research done in Germany aimed at finding a tipping point: discover the amount of insulation required to provide a measurable return on investment. Going beyond this when there was no longer an economic benefit made no sense. This economic ‘sweet spot’ is what distinguishes the Passive House from other green building codes. The movement is aimed at the mainstream not the financially elite.
CLEAN AND GREEN
For a Passive House to function properly and be fully certified, an experienced team is required. More and more professionals are being certified each year. The energy savings provided by Passive Houses meet even the most stringent greenhouse gas reduction targets. They are the way of the future yet the US has been slow to embrace the idea and opponents and misconceptions abound.
There is no doubt that there are still challenges to be overcome when these houses are built in extreme climates, but as research continues, solutions will be found. Potential problems such as excessive cold or humidity have to be carefully addressed at the design stage of a project by certified consultants to assess whether a project will be successful in achieving its energy and comfort targets.
I am lucky enough to live in Southern California, which is just as well since my house seems to have no insulation at all. It is colder inside than out in winter and hot inside in summer but we live in a wonderful climate with the doors and windows wide open all the time, so I am not complaining. If I still I lived in the Pacific Northwest, the idea of a fully insulated building that provides unmatched comfort, superb air quality, a tiny energy bill and a tiny ecological footprint would be very appealing.