Fossil fuels are becoming more difficult and risky to extract, the outlook for meaningful energy reform is cloudy, and the glaciers are melting. What's a green builder or green bucketer to do? Build or remodel a home to passive house standards.
A Passive House (or Passivhaus as they say in Europe) is a structure that employs a simple set of building technologies to achieve remarkable energy efficiency. Energy consumption is reduced by 90% or more compared to that of conventional homes. And these efficiency gains are not due to some weird building design. These homes are normal, comfortable living spaces which beauty can rival that of any other project.
This green building movement is about simplicity over complexity. Unlike with LEED, Passive House projects do not chase a list 'green' points. Instead the buck stops at actual energy use. Simply put, how much energy is required to build and operate a space?
The green building industry has long devoted itself to developing and using cutting-edge technologies, materials and methodologies. Sustainable builders routinely reclaim and upcycle materials, draw on LEED-accredited expertise, and strategize to minimize the environmental impact of construction work.
But as important as these endeavors are, the most important sustainability question in construction is, “what is the inking carbon carbon footprint of the finished product – a home's energy consumption?” Passive House projects address this question and offer practical, local solutions to big global energy problems.
In many ways, this represents a departure from the green construction industry's preoccupation with material choices: how sustainable is this bamboo? How local is this stone? What is the recycled content of that floor covering? All of that is important, but the environmental impact of a building's ingoing energy-use can dwarf those considerations. Passive House addresses this operational carbon footprint head-on.
Passive House homes minimize energy losses and maximize passive energy gains. These goals are reached by employing 7 principles:
- Eliminate “thermal bridges” (that allow heat and cool to travel through walls).
- Make the building envelope airtight.
- Use energy and heat recovery ventilation.
- Use high performance windows and doors.
- Optimize passive-solar and internal heat gains.
- Model energy gains and losses using Passive House computer modeling.
The result? All heating needs can be met by a single 1000-watt heater. That is like heating an entire home with your hair dryer. Heat from people, lights, appliances and the sun does the rest. The houses generate what aficionados call 'negawatts' because every bit of energy saved is equivalent to generating the same amount of energy at a power plant. Exception totally clean.
Check out these photos and case studies published by Passive House Institute US: