What Is Passive House?

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Passive House is an international building standard that requires buildings to use extremely low amounts of energy for heating and cooling purposes.

The passive house approach captures a thorough understanding of a building’s science. Buildings contribute to an overwhelming share of greenhouse gas emissions in New York City – an estimated total of 75%. It is essential for us New Yorkers to cut down on building energy consumption in an attempt to reduce the worst effects of climate change. There are six key methods to creating a passive house structure;

  • High-performance windows and doors with well-insulated frames
  • A super-insulated building facade, with a continuous insulation layer all the way around the building shell.
  • Thermal bridge free construction: requires careful detailing to minimize the weaknesses in the building envelope where heat can pass from interior to exterior or vice versa.
  • An airtight building envelope with meticulous attention to all connection details and use of the appropriate sealing materials to ensure airtight junctions.
  • Mechanical ventilation with heat recovery or heat and energy recovery to supply a constant stream of fresh air and/or exhaust the stale air without losing heat in winter or adding heat in summer.
  • Use of the Passive House Planning Package (PHPP) software to model a building’s energy losses and gains.

One of our top window manufacturers Zola Windows specializes in Passive House windows. The majority of energy-conserving windows fall into the category of double glazed. However, Zola has developed windows that boast three panes of glass, this significantly increases insulating power while using 90% less energy than conventional buildings. High performing windows as such, are a vital aspect of the revolutionary approach to sustainable design as they are extremely insulated and airtight.

Adler Windows Case Study: Brooklyn Heights Townhouse

Pre-renovation this townhouse was in such poor conditions that most of its historic details were already removed.  Adler Windows worked closely with Baxt Ingui Architects to replace all of the existing windows with brand new Zola Passive House windows.

Our experts selected and installed Zola’s thermo-wood tilt and turn windows and in-swing doors. For many clients, this product line hits the sweet spot in terms of value, performance, and craftsmanship.  Zola’s windows and doors have become the industry’s go-to choice for high-performance buildings. The Thermo range features an 88 mm deep frame and triple glazing which puts them at the top of the list when it comes to energy efficient fenestration products. 

New York City’s landmark preservation commission was very accommodating regarding the inclusion of Passive House principles in this townhouse renovation. To preserve the historic wood–frame doors, the front vestibule is isolated from the air-sealed envelope and an energy-recovery ventilator was included to introduce fresh air. The Brooklyn Heights homeowners are thrilled with how effortlessly comfortable and quiet their new home is. There is no tweaking of the thermostat and no waking up to the loud bustling noises of NYC – bliss!


Heating energy 2.04 kWh/ft2/yr 6.98 kBtu/ft2/yr

Cooling energy 1.11 kWh/ft2/yr 3.80 kBtu/ft2/yr

Total source energy 10.96 kWh/ft2/yr 37.41 kBtu/ft2/yr

Treated floor area 3,531 ft2