Building Design: Passive House vs. Conventional
A voluntary residential design and construction standard originating in Europe focused on maximizing performance of a home's thermal envelope in order to reduce the heating or cooling load to less than 4.75 kBtu/ft2-yr in any climate zone.
The Passivhaus standard was first conceived in 1988 from a conversation between two European University Professors. Through several research projects this concept was developed into a robust standard. As of 2010, an estimated 25,000+ structures have been built to the Passivhaus standard in Europe. The standard is applied to both residential and commercial buildings.
In 2006, the first home built to the Passivhaus standard In the United States was built in Bemidji, Minnesota. In the United States the Passivhaus standard is referred to as the Passive House Program (PHP). Despite its recent arrival to the United States market, the PHP has gained quick acceptance by several regional energy efficient construction advocates and associations throughout the country.
What sets the PHP standard apart from other nationally and regionally recognized energy efficient building programs is its rigorous focus on the performance of the building envelope. Most noteworthy is that the standard limits a home to 4.75 kBtu/sf/yr in primary energy for the heating load and 38.1 kBtu/sf/yr in primary energy for whole house energy consumption. These targets are achieved primarily by maximizing R-values, reducing or eliminating thermal bridging and limiting air leakage rates by improved process and improved air-sealing materials. In general, to achieve these targets, a Passive House will see R-values above 45 for walls, 65 for ceilings and 65 for floors with window U-factors between 0.1 and 0.2 in US DOE climate Zone 4-5 . Characteristics of the building encloser will vary significantly with climate. Design optimization and certification are verified with the use of a proprietary tool, the Passive House Planning Package (PHPP) which is based in an Excel spread sheet.
Energy Savings: 50%
Energy Savings Rating:
Limited Assessment What's this?
|1||Concept not validated||Claims of energy savings may not be credible due to lack of documentation or validation by unbiased experts.|
|2||Concept validated:||An unbiased expert has validated efficiency concepts through technical review and calculations based on engineering principles.|
|3||Limited assessment||An unbiased expert has measured technology characteristics and factors of energy use through one or more tests in typical applications with a clear baseline. |
|4||Extensive assessment||Additional testing in relevant applications and environments has increased knowledge of performance across a broad range of products, applications, and system conditions. |
|5||Comprehensive analysis||Results of lab and field tests have been used to develop methods for reliable prediction of performance across the range of intended applications.|
|6||Approved measure||Protocols for technology application are established and approved.|