According to NABERS, the Australian building rating system, buildings worldwide “use 40 per cent of the world’s energy, emit 40 per cent of the world’s carbon footprint, and use 20 per cent of the world’s available drinking water.”

In addition, the U.S. Environmental Protection Agency says buildings are responsible for 30 per cent of raw materials used, and account for 30 per cent of the waste stream.

“Green” or “sustainable building” aims to improve those metrics through changes to material selection, siting, energy efficiency, waste reduction, and indoor air quality, while creating healthy and efficient structures.

Many builders and building owners have worked to make their structures greener, caulking air leaks, adding insulation, and upgrading HVAC equipment with more efficient units. Over the last two decades, the field of building science has played an increasingly important role in improving energy efficiency. Best practices are now tested and evaluated, and rating systems such as LEED and Green Star provide a checklist for new construction to adhere to.

Since LEED was created in 2000, more than 20,000 LEED  for Homes projects have been certified. Green Star has certified more than 600 projects in Australia since its inception in 2003. And while both standards can demonstrate efficacy, both still carry the stigma that they increase costs beyond their value, making them appropriate only for high-end projects.

The Passive House standard, in contrast, is focused almost exclusively on minimizing each building’s energy use. It dispenses with the lengthy checklist in favor of standards for the building’s overall energy use, air leakage, and heating and cooling. It’s effective, cutting energy use by 80 to 90 per cent, but has also been labeled as overly expensive, and inflexible with design. Many Passive Houses are boxy modern designs.

Evidently, some builders are able to make the Passive House standard work with a traditional architectural design, at a cost comparable to more traditional and less energy-efficient building methods.

Adam Cohen runs Structures Design/Build in Roanoke, Virginia. One of his recent projects, a Craftsman-style home for Jason and Stephanie Specht of Thaxton, Virginia, has garnered considerable acclaim. The Specht home received the GreenBuilder Home of the Year Award for 2013 in the Best Mainstream Green category.

The Specht home, at 1800 square feet, with three bedrooms, two bathrooms, and attached garage, looks completely standard but is a certified Passive House and earned a HERS (Home Energy Rating System) score of 38. In comparison, a standard new home scores 100, and an Energy Star home scores 85 or lower.

Perhaps most surprisingly, the Specht home cost just $150 per square foot, thanks to extreme attention to detail and precise energy modeling software that almost exactly predicted the home’s annual energy use. Passive House certification, as mentioned, requires that a building meet strict standards for air leakage, energy for heating and cooling, and total energy use.

Meeting those standards has proven challenging for builders, but best practices include a super-insulated envelope, energy-recovery ventilation, high-performance windows and doors, and eliminating thermal bridging. Because Passive House buildings are so well insulated and air tight, heating and cooling systems can often be downsized for cost savings. In fact, some Passive Houses have even replaced the furnace altogether in favor of small, wall-mounted plate heaters totalling about 1500 watts.

Cohen’s approach makes use of all those elements while minimizing the use of non-standard materials. Some parts of the home are high end products, such as the imported windows and doors from Klearwall Industries, but Cohen says most of the house makes use of readily available components.

“What really is my secret sauce, it’s not the product, it’s the process,” Cohen said. “We take 100 per cent responsibility for everything, design, construction, commissioning, and monitoring.”

By designing and building the home, therefore, Cohen’s team can control more construction details to maximize performance and minimize costs.

At $150 per square foot, the Specht home compares favorably with a standard home. The National Association of Homebuilders 2013 survey results peg the average newly built US home at just under $400,000 and 2607 square feet.

In addition to building energy efficient homes and other buildings, he serves the Passive House Institute US as vice-chair of the technical committee, and trains other architects and builders in energy-efficient design and construction.

  • the minor additional cost of involving a consultant who is able to deliver analysis of the sustainable home design and is able to tweak the design to provide the best performance of the building is extremely small in comparison to the ongoing savings in running costs and the potential to save in capital costs during construction as well.

    If you look at a home as a product, the way most mass scale builders look at a home, there are similarities to the production process of a car.

    A car is an optioned product that is optimized for fast efficient production but offers flexibility and choice for the consumer while minimizing the waste stream.

    Similar methods and principles should be applied to the process of design for buildings to achieve the same outcome, a product that is flexible, meets the consumers needs and has a minimal impact on the environment.

    Of course a car as a product is a poor example of sustainable transport, however there are many valuable lessons to be learnt from the process of design and manufacture of a car that are currently being applied in the construction industry.

  • While there is long term payback, these systems do cost more initially. However, there are often expensive items chosen purely for aesthetic reasons, that can be sacrificed.
    I had a client who, rather than install a solar water heater, spent the money on more expensive windows. At the lower end of the scale, these things do add to the cost, and need to be looked at as long term savings.

  • A good article. Cutting edge design, materials and techniques are important for saving energy in new buildings. However, significant reductions in energy use will require a broader perspective.

    First, the US Environmental Protection Agency published a report showing that location efficiency trumps individual building efficiency in terms of overall household energy consumption.

    Second, there are more existing buildings than new ones. So encouraging energy-saving retrofits to existing buildings is also very important.

    Regarding both factors mentioned above, property tax reform can encourage more compact, energy-efficient development patterns while also reducing the cost of energy-saving retrofits. This is accomplished by reducing the tax rate on privately-created building values and increasing the tax rate on publicly-created land values. Thus, without losing any revenue, communities can encourage more affordable and compact development while reducing the costs associated with energy-saving retrofits.