The Passive House: Page 4 of 4

Evaluate Energy Gains & Losses

The Passive House Planning Package (PHPP) is an energy-modeling tool that helps integrate each PH component so that the final design will meet PH requirements. The PHPP starts with the whole building as one zone of energy calculation. The designer inputs all of the house’s basic characteristics, including orientation, size, window location, insulation levels, and so on. The PHPP then computes the energy balance of the design. If needed, the designer can change a house’s components within PHPP to model the impact of those changes on the overall energy balance. The PH standard is met when:

• the space heating and cooling requirement of the design is less than or equal to 4.75 kBtu per square foot per year (15 kWh/m2/yr.); 
• the primary energy demand of the design is less than or equal to 38 kBtu per square foot per year (120 kWh/m2/yr.); and
• the airtightness of the building is at or below 0.6 ACH at 50 Pa.

The PHPP also effectively models solar water heating for combined space and domestic water heating, natural ventilation (such as night cooling), and the efficiency of energy recovery ventilation.

Up-Front Costs & Energy Savings

Among all the components that contribute to increasing the efficiency of a home’s thermal envelope, high-performance windows and doors cost the most. Upgrading from double-pane vinyl-framed windows to high-performance fiberglass windows with insulated frames and triple-pane, argon-filled glazing can cost an additional $10,000 or more for a typical home. Interestingly enough, high-end architectural wood-frame, double-pane window packages upgraded to European high-performance specifications cost only about 10% more.

Costs for a house built to both PH and green standards will be 10% to 15% higher than for a house built only to PH standards. In a green-built home, many types of standard materials are replaced, and often these increased costs exceed the costs of energy-efficiency features.

With a focus on energy efficiency and conservation, a PH can get by with a smaller, and therefore less costly, renewable energy system, putting net-zero energy (or even net-positive energy) and carbon-neutrality within reach.

From Concept to Reality

In Europe, thousands of homes have been built or remodeled to meet the PH standard, while in the United States, PH design has just begun—but it has the potential to have a dramatic impact on the nation’s energy use. Residential energy use constitutes about one-fifth of the total U.S. consumption, and space heating and cooling of U.S. homes represents more than half of a household’s total energy use.

Access

Katrin Klingenberg is the cofounder and executive director of the Passive House Institute US, which promotes the Passive House standard. She designs and consults on Passive House projects across North America, and is a licensed architect in Germany.

James M. Kernagis is the cofounder and program director of the Passive House Institute US. He was one of the first builders to adopt and build to PH standards, including the nonprofit Ecological Construction Laboratory’s building.

Architecture 2030 Challenge • www.architecture2030.org