Passive House: High Performance Construction Standards in the US

Passive House Design [founded in the US, then developed in Germany as Passivhaus] is different than passive solar design since insulation and heat exchangers are utilized while solar energy plays a lesser role.

Passive House Design: Introduction and History

In the United States, passive house design standards dictate space heating energy of 1 BTU per square foot (11 kJ/m²) per heating degree day which equates to 75-95% less energy for space heating and cooling than current new buildings that meet today’s US energy efficiency codes. [1] Typical strategies implemented to achieve the standard include well insulated envelopes coupled with air barriers, air sealing, and the use of heat exchangers to recirculate indoor air. Other considerations include: passive solar design, landscape design, advanced window technology, airtightness, ventilation, space heating from internal heat sources such as equipment and people, lighting and appliance efficiency.

 

 

Passive Building Attributes

Advantages of passive buildings include fresh, clean air, homogeneous interior temperature, slow temperature changes, and low energy loads that support renewable energy sources. Passive buildings could be up to 14% more expensive upfront than conventional buildings. [2] However, when designed to balance budgets, the mechanical system costs and alternative energy system costs are reduced. These reductions in system costs off-set the money spent on better insulation, windows and doors. And, owners get the payback dollars for insulation, windows and doors permanently in the building, as opposed to spending money on replacing mechanical and alternative energy systems 13-15 years down the road (just as they started getting pay-back!).

 

Passive House Design Process

Buildings can be certified as Passive with the help of a CPHC (Certified Passive House Consultant) via the Passive House Institute US (PHIUS) or Passive House Academy US (PHAUS). Both residential and commercial buildings utilize the Passive House model.

 

Passive Building: Principals

Passive building comprises a set of design principles used to attain a quantifiable and rigorous level of energy efficiency within a specific quantifiable comfort level. “Maximize your gains, minimize your losses” summarize the approach. To that end, a passive building is designed and built in accordance with these five building-science principles:

• It employs continuous insulation through its entire envelope without any thermal bridging.
• The building envelope is extremely airtight, preventing infiltration of outside air and loss of conditioned air.
• It employs high-performance windows and doors
• It uses some form of balanced heat- and moisture-recovery ventilation and uses a minimal space conditioning system.
• Solar gain is managed to exploit the sun’s energy for heating purposes and to minimize it in cooling seasons.

Passive building principles can be applied to all building typologies, from single-family homes to apartment buildings to multi-story offices and skyscrapers.

 

 

Passive Building Benefits

Passive buildings offer tremendous long -term benefits in addition to energy efficiency:

• High levels of insulation and airtight construction provide unmatched comfort even in extreme conditions.
• Continuous mechanical ventilation of fresh filtered air assures superb air quality.
• A comprehensive systems approach to modeling, design and construction produces extremely resilient buildings.
• Passive building is the best path to Net Zero and Net Positive buildings because it minimizes the load that renewable energy sources are required to provide. [3]

Click here to watch a 90-second video explaining the “Passive House”

[1] Waldsee BioHaus architect, Stephan Tanner

[2] “Passivhäuser im Bau bis zu 14% teurer”. Franz Alt. Retrieved 2009-06-05.

[3] www.phius.org/what-is-passive-building-/the-principles

 

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