Passive House and BEopt

I am working on our first Passive House project. This project is scheduled for construction next year, in the Bangor, Maine area. While I have been designing buildings that meet ASHRAE 90.1-2009 buildings for a while, and even buildings that incorporate most features of ASHRAE 189.1, this is the first building in our office that strives to meet Passive House standards.
In embarking on this project, I naturally started doing research on Passive House. It appears criteria for certification to Passive House Institute- US standards is less than a year old. Documents available online suggest PassiveHaus- the German program for constructing low-energy-use dwellings- did not translate well to the United States. PHI-US realized this several years ago. Working with the Department of Energy (DOE) and Building Sciences Corporation (BSC), PHI-US set about to develop standards that followed the spirit of PassiveHaus, but had applicability in the US.
The major areas to be addressed were the relationship between designing for peak heating and cooling as well as annual heating and cooling loads; the wide variation in climates throughout the United States; and the availability of cheap photovoltaic renewables to the US residential market. In Germany in the 1990s, less variation existed between peak and annual loads, less variation existed in climate types, and PV renewables were not cheap.
Thus, PHI-US has developed over 100 different maximum energy use thresholds for the US, based on Typical Meteorological Year (TMY) data in the US with sufficient data to use in the energy modeling program WUFI. The TMY data can also be used in DOE2 and EnergyPlus.
Notably, the PHI-US climate-specific thresholds were set by using BEopt, a residential energy analysis program from DOE that sits on top of either DOE2 or EnergyPlus. One of BEopt’s distinguishing features is the ability to test an energy efficiency measure’s return on investment. BEopt is not interested in wildly expensive features. It is interested in features that make sense. Thus, BEopt output includes calculations on an energy efficiency measure’s impact on energy savings in dollars and BTUs, but also the impact on ones mortgage. At a certain point, the cost of saving a BTU of energy through EEMs is more expensive than the cost of creating that energy using renewables.
Thus, PHI-US has decided that the energy use intensity calculation of a residence should include credit for renewables.

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Architect

Principal at Sealander Architects, Ellsworth Maine. Revit guru. Married with 3 children. Avid gardener. Lived in San Francisco for nine years. Master in Architecture from Columbia University Bachelor of arts in religious studies, Wesleyan University. Graduated Staples High School, Westport CT. Hope to spend some time in Hokkaido before all is said and done.