Passive House

Passive House, the German energy rating system, is focused strictly on energy, but it offers a great model for other rating systems. The rules are relatively simple: provide a building that uses less than 4.75 kbtu per sf per year each for heating and cooling, consumes less than 38.0 kbtu per sf per year total source energy, and passes air tightness testing at the rate of 0.6 air changes per hour @ 50 pascals (0.6 ACH50). There is no roadmap that tells you how to get there - the rules are not written with an answer in mind, your project just has to get there! In addition, the solutions change with your building's orientation and climate. This description makes Passive House seem simple when in fact the process is pretty challenging. There is a preliminary review of the energy model by PHIUS to screen for large mistakes, and three to four visits from a rater with a blower door and inspections of the envelope and all of the MEP systems (commissioning). Passive House shifts the focus from suggesting a solution, to a review of the work and verifying the building's design in the field. The bulk of the money spent in certification is spent on verifying that the project is modeled and built as designed. Once you have decided to make a Passive House project it is an all or nothing pursuit, there is no going halfway. Passive House is a complete building system; it is not an a la carte menu like LEED. Once you have decided to make a Passive House, most of your decisions need to take that fact into account.