While the terms green and sustainable are often used interchangeably, not all green building techniques are sustainable. Green building encourages the reduction of harmful impacts that buildings have on the environment and their occupants while focusing on environmental sustainability, but does not necessitate truly sustainable practices. While sustainable strategies stipulate the conservation, or preservation, of resources and require the reconciliation of all economic, social, and environmental demands. There is a need for the establishment of a framework that encourages economic, social, and environmental sustainability for green buildings.
Recently, through a post on a green building community forum, an interesting viewpoint regarding the definitions of green building and sustainability emerged. The poster asserted that what passes for green is almost never even close to sustainable. I would like to take this opportunity to evaluate this statement, these terms, and their connotations in the context of residential design and construction.
A United Nations commission stated that sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs. Obviously, this is a broad spectrum definition and leaves room for interpretation and refinement. A more utilitarian definition implies that sustainability relates to a method of harvesting or using a resource so that the resource is not depleted or permanently damaged – simply defined as resource conservation.
According to the U.S. Environmental Agency (EPA), green building is the practice of creating structures and using processes that are environmentally responsible and resource-efficient throughout a building’s life-cycle from siting to design, construction, operation, maintenance, renovation and deconstruction.
Many other widely accepted definitions adopt basic tenets to define green building as a system that is fundamentally centered on specific concepts: energy efficiency, resource efficiency, durability, indoor environmental quality, water conservation, and site development.
Evaluation of Correlation
Often used interchangeably, the terms green and sustainable are, in fact, not synonymous; all green building techniques are not sustainable, but all sustainable initiatives are inherently green. Green building encourages the reduction of harmful impacts that buildings have on the environment and their occupants while focusing on environmental sustainability, but does not necessitate truly sustainable practices. Sustainable strategies stipulate the conservation, or preservation, of resources and require the reconciliation of all economic, social, and environmental demands.
Net Gain Approach
In my opinion, it is appropriate to say that green solutions, as defined by current practices, attempt to contribute to a sustainable system.
For example, the popularity of spray-applied polyurethane foam (SPF) has dramatically increased and it is now regularly specified by architects, green builders, and consultants and accepted by the majority of the current green building certification programs as a sensible green solution.
Understandably, the increased energy-efficiency and thermal and air sealing characteristics are seen to outweigh the environmental effects that result from the high embodied energy required to manufacture the product, the effect of petrochemicals that are most commonly associated with SPF, the global warming potential (GWP) of many of the blowing agents, and the potential for off-gassing.
By comparing the GWP and the embodied energy used to manufacture and apply the product with that of the energy saved as a result of the calculated energy use reduction, it is feasible that an environmental payback period could be established. In many senses of the definition, SPF is a green material; however, regardless of the payback period, sustainability might be a hard sell.
In many cases, the effectiveness and validity of green solutions seem to be evaluated in reference to the desired objective – energy-efficiency, durability, occupant comfort, resource efficiency, for instance. The industry often takes a net gain approach or simply settles for a solution that is “better that conventional methods” instead of evaluating each solution based on its comprehensive merit. This is not to say that, as an industry, we will ever truly reach total sustainability, but every opportunity to make each green practice holistically sustainable should be pursued.
In order for green to approach sustainability, the focus of the industry must be realigned to respond to the areas with the highest potential for environment degradation associated with the built environment and to embrace the preservation and adaptive reuse of existing structures. It must be understood that building a sustainable home – considering initial embodied energy, operational energy, resource consumption, land consumption, and so on – in the current production oriented environment is not only very uncommon, but also relatively impractical; although, rethinking the way that homes are designed and constructed and incorporating green strategies is very feasible from an economic and environmental perspective.
The impending challenge is addressing the areas that will provide the largest impact. As quoted by Martin Holladay from Green Building Advisor, Stephen Thwaites writes that “over the first 50 years, the initial embodied energy is less than 1/12 of the operating energy.” This statistic provides very little obscurity regarding where the focus must be placed – and no, it’s not on the most environmentally friendly countertop or flooring. We must focus on the operational energy use of our homes: first, by siting our buildings and establishing passive solar strategies, then by improving building enclosure efficiencies, eliminating mechanical inefficiencies, and reducing consumption.
From a development standpoint, the most sustainable option is to preserve, renovate, and reuse existing structures, especially those of historic significance. Not only does this process reduce energy consumption and waste generated from demolition, but it also maximizes the use of existing materials and infrastructure, engages the local workforce, and preserves the character and craftsmanship of earlier eras. By utilizing one of the most abundant and commonsense renewable resources, existing buildings, the focus can then be shifted from construction-oriented green approaches to performance improvements and the control of the operational energy usage of existing buildings, with their initial
embodied energy still very much intact.
Beyond the Environment
Preserving our heritage and encouraging a vibrant future – architecturally, culturally, and environmentally – is fundamental to the pursuit of social sustainability. The green movement must strive to not only enable an environmentally sustainable future, but also to preserve and create places that inspire the cultivation of economic, cultural, and social endeavors. Energy retrofits and high performance homes provide an opportunity for tradespeople and homeowners to directly and indirectly stimulate local economies, have the ability to provide a sense of accomplishment and togetherness in the approach of a common goal, and promote civic, cultural, and economic development in affected areas.
Green signifies an effort to be sustainable. We must first establish environmental priorities for each project and then extend those efforts into a framework that encourages economic, social, and environmental sustainability. As consumers, designers, builders, and consultants, it should be our goal to identify, evaluate, and embrace all legitimate green applications in an attempt to facilitate a transformation into a more sustainable future.
In my opinion, what you call it isn’t important; any effort to reduce negative impacts on the environment, communities, and society, in general, through design and construction should be embraced – green or sustainable.
© 2010, Jed Peterson. All rights reserved. Do not republish.