Integrated design strategies for sustainable buildings
The materials we use to create our buildings and the energy we consume to operate them take a tremendous toll on the environment. According to the U.S. Energy Information Administration, approximately 76 percent of all electricity generated by power plants goes toward operating buildings. Buildings also account for an estimated 48 percent of all greenhouse emissions, compared to 27 percent for transportation and 25 percent for industry.
We in the building design and construction world cannot afford to ignore these truths. In fact, we are uniquely positioned to address them in an effective way by having professionals from multiple disciplines work together on a project from the onset. This process is called “integrated design.”
An integrated design team can consider alternative design and building strategies and look for creative ways to incorporate them into our projects from the beginning. We can weigh the costs and benefits of such strategies and seek out a range of solutions that allow each component of the building to have more than one purpose and work synergistically to maximize the benefits realized.
Improving sustainability and energy efficiency in buildings can be achieved at many levels. Among them are fundamental low-cost or no-cost strategies which, if considered properly, should not add significant cost to the project:
• Site selection and building location: The integrated team should be involved in the site selection for any building project. It is always worthwhile to consider adapting or reusing an existing building before investigating natural or unbuilt sites for a project. If you are looking at a natural site, however, be careful to avoid development on prime farmland, parkland, habitat for endangered species, or near a wetland. Infill properties, vacant lots and brownfields should always be considered and are often well-situated and rewarding properties to develop.
• Solar orientation: Locate your building on the site to maximize solar exposure and natural light while minimizing impact on that site. Align the building along an east-west axis so most windows face either north or south. In northern climates, like New Hampshire and Vermont, design smaller, better insulated windows for the north façade, while the south façade glazing may be expansive to maximize solar heat gain. Use building overhangs and/or sunscreens to help regulate natural light and heat gain.
• Minimize square-footage: Focus on quality of space over quantity. Share functions wherever possible. Design an open layout where users feel a more expansive space, while their dedicated work area may be smaller.
• Save mature trees and plantings: Preserve existing trees to help shade your building and protect it from sound, smell and visual distractions. Aesthetically they will enhance your project, save money and conserve energy required to transport and replant trees and shrubs.
• Minimize paving: Paved areas are often expensive to install and maintain. They create heat islands and require significant infrastructure to deal with stormwater runoff. Where paving cannot be avoided, consider a pervious pavement solution and/or bioretention for storm water treatment.
• Use water and energy-efficient fixtures: Rarely are efficient plumbing and lighting fixtures more expensive. On large commercial projects, consider using waterless urinals, dual-flush toilets and sensors for lavatory faucets.
• Maximize daylight opportunities: Wherever possible, use skylights, light tubes, and light shelves to bring light deeper into the building.
• Consider materials: Specify standard or stock sizes to minimize waste. Whenever possible, use local products to help stimulate the local economy and reduce transportation. Reuse whatever you can, or specify materials with a high post-consumer or post-industrial recycled content. And don’t forget to think about the embodied energy of a product — it may be friendly in some respects but take a whole lot of energy to manufacture and transport to your job site. Finally, use low or no-VOC (volatile organic compound) products to minimize indoor air contaminants.
• Eliminate unnecessary finishes: Consider a polished or stained concrete floor before you cover a slab with carpet or linoleum. Are ceilings really necessary in a space —could you expose structure, ductwork?
• Natural versus mechanical ventilation: Design buildings to promote cross-ventilation and ‘stack effect’ air circulation. This means using operable windows and making sure your clients have the ability to coordinate opening such windows at appropriate times.
Many green building strategies do have an up-front cost. Here are some strategies that seem to be very worthwhile and are easily measured in terms of their return on investment.
The most important energy-saving measure for a building is to design a tight, well-insulated building envelope, especially in climates that experience extreme cold or heat. This allows for a reduction in the size and capacity of mechanical systems.
When designed appropriately, mechanical systems, lighting controls, and well-thought-out zoning can save a bundle. Think about how and when a building is occupied. Use lighting controls and occupancy sensors to adjust lighting. Use direct digital controls to regulate HVAC systems according to occupancy and program. Introduce multiple zones for heating, ventilating, and cooling based on type of space and solar orientation.
Once you’ve done everything else, the following, more active approaches should be considered:
• Solar electric and hot water
• Wind Power
• Water collection, retention, and reuse
• Geothermal heating systems
Active strategies require more significant up-front investment and are often limited in their efficacy. That said, the technologies, their popularity, and the incentives being offered to promote them are increasing every day.
By designing and constructing sustainable buildings, we are redefining the quality of buildings in general. An integrated approach to these projects makes it easier to lessen our impact and increase our contribution to the overall global system. Remember, we are not mere inhabitants of this planet, we are its shapers.
Andrea Murray, an architect and planner at Bread Loaf Corp., a planning, architecture and construction firm based in Middlebury, Vt., also teaches architectural design at Middlebury College.