- Case Studies
- Home Performance
- Energy Audits
- Air Sealing
- The Economics of Energy Efficiency and Renewables.
- High Efficiency Windows
- Home Certifications
- Remodeling and Energy Efficiency
- Contact Us
April 10, 2015
What does the term "green building" mean? It's generally understood to encompass buildings that are "designed, built, renovated, operated, or reused in an ecological and resource-efficient manner."See CalRecycling. This blog post is an attempt to unpack this definition and identify the core practices and considerations that go into designing and building a sustainable structure.
The first consideration is where the property is located. Will the inhabitants of the building be able to walk to nearby shops, restaurants, and centers of employment? Or, alternatively, will they need to drive their cars everywhere? A sustainable site will be within close proximity to public transportation options (known as "transit-oriented development") and within walking distance to places of work and entertainment (high walkability). Many real estate websites, such as Zillow, assign a "walkabibility" score to parcels of land, which indicates the degree to which someone would need a car for his/her daily activities.
A second factor relating to site sustainability is how the land has been historically used. Urban infill development, which refers to projects where previously-developed land is repurposed for a new project, is a green option. Natural habitat isn't destroyed and urban sprawl is limited. Similarly, brownfield sites, which are places that were once polluted by industry, can be cleaned up and used for residential or commercial purposes in certain circumstances. Remediation of a brownfield site is expensive, but can be worth it when the location is valuable, such as when an old shipyard on a city's waterfront is redeveloped into condos or offices.
Energy Efficiency & Renewable Energy
With regard to energy, a building can be evaluated by how efficiently it uses energy as well as how much energy it produces via renewable means. The most sustainable building would be net energy positive, meaning it produces more energy than it consumes.
Energy efficiency is achieved by implementing a number of strategies including:
- Creating an air-tight building envelope through air sealing techniques;
- Properly installing insulation with an R-value appropriate to your climate zone;
- Installing well-designed HVAC and mechanical systems;
- Managing solar gain/loss by positioning of climate-specific glazing and/or shading; and
- Using ENERGY STAR appliances.
With regard to single family homes, renewable energy is typically produced by installing:
- Photovoltaic solar arrays;
- Solar thermal systems;
- Small-scale wind turbines; or
- Geothermal systems.
With droughts occurring throughout the southwest and western regions of the United States, water conservation has become a critical component of green building. Common water saving strategies include:
- Implementing a greywater system, which uses household water for purposes like flushing toilets or irrigation;
- Installing low-flow faucets, shower heads, and toilets; and
- Planting native, drought-resistant plants and avoiding lawns that require regular watering.
Building materials and finishes can be "green" in many different ways. An ideal product has some combination of the following elements:
- Made from recycled materials;
- Made from readily renewable materials (i.e. bamboo);
- If wood, harvested using responsible logging techniques (FSC Certified);
- The manufacturing process requires minimal energy; and
- Produced locally with short transit to the job site.
On a related note, every effort should be made to recycle demolition or building debris during construction. Some municipalities reduce building permit fees when a certain percentage of refuse is diverted from landfills.
Climate Change is causing increasingly severe weather events, which have decimated traditionally-built buildings (think Hurricane Sandy). An effort is now being made to construct buildings to withstand greater winds, flooding, and power outages, which all fall under the umbrella of "resiliency." Obviously, a building that can withstand megastorms is more sustainable, as it doesn't need to be rebuilt as often.
Indoor Air Quality
Healthy indoor air is an important component of green building. When building envelopes are tightly sealed, fresh air must be introduced. By reducing leaks and effectively managing air pressure, occupants have greater control over the quality of the air entering the house through mechanical ventilation.
Furthermore, green building products typically don't have high levels of volatile organic compounds (VOCs), which are often used in particle board, paints, resins and glues. VOCs, such as formaldehyde or acetone, evaporate into the air and get breathed in by the building's inhabitants. Inhaling VOCs can lead to acute illness (intermittent headaches) or chronic diseases (cancer or liver damage). By minimizing VOCs and managing air flow in your home, you can better promote health and well-being.
Some practitioners in the Green Building Industry take a holistic view on sustainability and think about community impact when designing projects. Does your building design promote neighborhood interaction and engagement? An example of this concept is "the return of the front porch," whereby front porches are maximized and front facing garages are minimized. Folks siting on their porch can interact with neighbors and people on the street, which contributes to a sense of connectedness and support.