The term “Passive House” has become more frequent in the green building industry, but there is often confusion about its application. Despite its title, the Passive House building standard can be applied to office buildings, schools, supermarkets, residences, and more. It’s becoming more popular and it’s happening here in Pittsburgh.
What is Passive House?
Passive House (or Passivhaus, in German, where the standard originated) is a voluntary standard for building efficiency that results in little energy for heating and cooling. Building built to Passive House standards are often likened to carrying water in a bucket instead of strainer – the building envelope is so effective that the occupants’ own body heat is a significant source of heat and, in some cases, may be sufficient to heat the building. These buildings are not completely passive, as they need to have active ventilation and heating system, although the size of the heating system is significantly reduced.
Passive House is in good company with other building standards like LEED (Leadership in Energy and Environmental Design), Living Building Challenge, and WELL, among others. While other standards focus on environmental impacts or human health, Passive House focuses almost entirely on building design, especially the building envelope, in order create highly efficient buildings. Although, energy efficient Passive House buildings do inherently have a reduced environmental impact during the use phase of the building due to reduced energy consumption.
Passive House is an important building standard because as our resources become increasingly finite, especially those used traditionally for heating and cooling a building, consuming what is left conscientiously and frugally will help to foster a gentler transition to other technologies. In traditional construction, more energy is required to put into the building to keep up with the heating and cooling demands of the building. A building built to Passive House standards required a small amount of energy to keep it operating at a comfortable temperature.
What are the certifying organizations?
Two organizations administer Passive House certifications – the international Passive House Institute (Passivhaus Institut, PHI) and the national Passive House Institute U.S. (PHIUS). Before 2011, PHIUS was effectively the U.S. branch of PHI, but as of 2015 PHIUS has developed standards that differ from PHI. The main ideological difference that split the two organizations is that PHI has a one-size-fits-all, straightforward standard that all buildings must meet, and PHIUS has developed climate specific standards. PHI is an international organization that was established before PHIUS and, thereby, has more certified buildings, specifically commercial buildings, than PHIUS.
While more than 30,000 projects have been certified under the international Passive House standard, there are currently only 126 certified or pre-certified PHIUS Passive House projects in the United States — and four of them are in Western Pennsylvania. However, many other regional buildings utilize Passive House strategies without obtaining either the international or U.S.-based certification. Learn more.
What are the requirements to meet the Passive House standard?
The standards developed by PHI are uniform across climates, and are older and more established, so they are the standards presented here.The standard requires the building to be nearly air tight (0.6 air changes per hour at 50 pascals), with minimal heating and cooling loads (both caped at 15 kWh per square meter per year), and a total maximum source energy for all purposes of the building of 120 kWh per square meter annually. The tight building envelope reduces infiltration, reducing heating and cooling loads, but also necessitating a ventilation system to bring in fresh air to ensure good indoor air quality.
What credentials are out there?
Through both PHI and PHIUS, there are a range of credentials available to engineers, architects, builders, tradespeople, raters, and verifiers. PHIUS manages 4 professional training certifications to help practitioners achieve Passive House in the residential sector: Certified Passive House Consultant, PHIUS Certified Builders Training, PHIUS+Quality Assurance/Quality Control Professional Training, and PHIUS+Large Building Verifier Training. The International Passive House Association manages similar trainings and credentials, but they are more focused on the commercial sector: Certified Passive House Designers and Consultants, Certified Passive House Tradespeople, and Passive House Building Certifiers.
In Western Pennsylvania, there are currently 28 people (representing 21 different firms) holding credentials through the U.S.-based PHIUS group: (17) Certified Passive House Consultants, (8) PHIUS Certified Builders, and (3) PHIUS+Raters. Meanwhile, there is only one person in the region who holds a credential with the International Passive House Association (he does not overlap with any PHIUS credential holders).
What is GBA doing?
GBA is offering Certified Passive House Designer and Consultant training through the PHI’s educational platform: International Passive House Association (iPHA). We are offering the international Passive House training, as it is more widely applicable to our stakeholder base with its commercial applications and acceptance worldwide.