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Passive House
The Passive House Difference
Passive House is a building standard for creating highly energy-efficient homes and buildings.
The Passive House standard is based on the principles of using insulation, air-tight construction, and energy-efficient heating and cooling systems to significantly reduce a building's energy consumption. The goal is to create a comfortable indoor environment while reducing energy use and minimizing the building's carbon footprint.
Passive House buildings typically have thick insulation, high-performance windows and doors, and a well-sealed building envelope to reduce energy loss. They also rely on mechanical ventilation systems with heat recovery to maintain healthy indoor air quality.
The Passive House standard is rigorous and requires buildings to meet strict energy efficiency requirements. For example, a building must have an annual heating demand not exceeding 4.75 kBtu/yr·ft2 and overall annual energy demand not exceeding 19 kBtu/yr·ft2 of living space. Additionally, the building must be designed to achieve a maximum air leakage rate of ≤ 0.6 air changes per hour at a pressure difference of 50 Pascal.
The Passive House standard has gained popularity worldwide, and there are now tens of thousands of Passive House buildings around the world. The benefits of Passive House buildings include reduced energy costs, improved indoor air quality, and a lower carbon footprint.
Passive House Design Principals
Airtightness:
PH threshold for air-tightness is ≤0.6 ACH50 (air changes per hour at 50 Pascal) / Evaluated through blower door test / Prevents humid air from entering the construction and possibly causing structural damage due to interstitial condensation Airtightness / Reduced cold air infiltration in the winter will reduce heating demand / Reduces drafts which leads to higher comfort levels / Reduces noise infiltration
Thermal Insulation:
Interior, exterior, roof and foundation insulation work as part of the overall system to stabilize the internal temperature of the house
Reduce Thermal Bridges:
Thermal bridges occur where there are penetrations of the insulation layer by a material of low resistivity or high conductivity and/or a change in the insulation thickness / Passive House has defined "thermal bridge free" construction as construction with a Psi value equal or less than 0.006 Btu/(hr · ft · F) Thermal Bridge Types / Geometric - whenever the envelope plane changes by greater than 60 degrees / Construction - wherever structural or aesthetic elements puncture the insulating plane / Repeating - such as a 2x8 stud wall
High Performance Glazing:
Typical U-value installed of <0.14 Btu/hr · ft 2 · F / Triple paned windows / SHGC - Solar Heat Gain Coefficient is the physical property of glass itself that expresses the amount of solar energy (heat) that passes through the window from 0-100% / Colder climates require a SHGC between 60-50% / Warmer climates require 20-30% SHGC / Recommend glazing for residential projects is 15-20%
Efficient Ventilation:
The energy recovery ventilator prevents the accumulation of VOC's, pollen, radon gas, smog, mold, fumes and odors by constantly exhausting the indoor air and exchanging it for filtered outdoor air. This ensures the indoor air quality is always fresh and comfortable.