Posted on December 29, 2014 by Carl Seville, GBA Advisor
I make no claim to being an expert on Passive HouseA residential building construction standard requiring very low levels of air leakage, very high levels of insulation, and windows with a very low U-factor. Developed in the early 1990s by Bo Adamson and Wolfgang Feist, the standard is now promoted by the Passivhaus Institut in Darmstadt, Germany. To meet the standard, a home must have an infiltration rate no greater than 0.60 AC/H @ 50 pascals, a maximum annual heating energy use of 15 kWh per square meter (4,755 Btu per square foot), a maximum annual cooling energy use of 15 kWh per square meter (1.39 kWh per square foot), and maximum source energy use for all purposes of 120 kWh per square meter (11.1 kWh per square foot). The standard recommends, but does not require, a maximum design heating load of 10 W per square meter and windows with a maximum U-factor of 0.14. The Passivhaus standard was developed for buildings in central and northern Europe; efforts are underway to clarify the best techniques to achieve the standard for buildings in hot climates., but ignorance has never stopped me from expressing my opinion before. Among the major complaints about the Passive House standard is that it has inflexible energy use requirements, and the European-designed program does not effectively address the wide range of U.S. climate zones. This inflexibility often leads those who pursue this certification to install enormous quantities of insulation, particularly under slabs, which raises a variety of questions and concerns about the usefulness of this practice.