There’s a lot more to a story than what the blurb at the back of the book tells you. The same is true of things that are marketed as “green”—they tend to have labels telling us that they’re sustainable, while the full story is much more complicated.
If you’re like many of us trying to live a more environmentally conscious lifestyle, you’ve come up against the complexities of trying to make greener choices. Do you purchase the organic produce that had to be trucked in or the local produce grown with pesticides? Both are “green” options, but how “green” are they?
There often aren’t clear answers about what makes one choice more sustainable than another. When we’re talking about kale, the stakes are pretty low, but they get exponentially higher when it comes to building or renovating a home.
Green builders often wade through these tricky waters in trying to construct sustainable buildings, partly because of the complicated and interconnected nature of building components and processes.
So it’s no surprise then that the industry has embraced the life cycle assessment (LCA) as a way to accurately analyze the full lifespan of a building in its entirety rather than just looking at the sum of the parts that went into the building itself.
This post will explore LCAs and how we can use them to help us make building and renovating decisions we can feel confident about.
What Is a Life Cycle Assessment?
A life cycle assessment is a methodology used to measure the impact that a product or process has on the environment, from the beginning of the process (raw material extraction) to the end of the process (disposal). These assessments can be used to analyze anything from building materials to furniture.
LCAs are used to measure both material and energy inputs and outputs, evaluate the effects of those inputs and outputs and formulate the data into useful information for understanding the outcome of a particular product or process on the air (i.e. ozone depletion), land (i.e. waste) or water (i.e. pollution).
Some Background on Life Cycle Assessments
Some aspects of LCA were in use as far back as the 1960s, but the comprehensive technical framework that we know now has been evolving since the 1980s.
Society of Environmental Toxicology and Chemistry (SETAC) is largely responsible for developing LCA into what it is today, though a great number of other organizations have also been involved in its development, such as Environment Canada and the Canadian Standards Association in Canada and the EPA in the U.S. The International Organization for Standardization (ISO) have taken LCA a step further by developing international standards for the methodology.
Benefits of an LCA
Assessing environmental impact is deceiving. Though it’s easy to see how bamboo flooring is a better option for the environment than a typical carpet, assessing the sustainability of two similar bamboo floors isn’t so obvious unless conducting an LCA.
How far did the flooring travel before eventually getting installed? How much embodied energy went into it? What effect will its disposal have?
Though one product on the surface could appear to produce more carbon emissions, when its entire environmental impact is taken into account (e.g. effects on air, land, and water) it could be far less harmful for the environment than the product that emits less carbon.
Life cycle assessments are a potent tool green builders can use to choose the most environmentally sound products and processes. LCAs analyze what the effects of a transfer from one medium to another is, such as eliminating air emissions by creating a wastewater effluent.
This way they can track what happens with individual components of a building to come up with accurate data on the sustainability of an entire building over its entire life cycle.
Information is power. Empowered by the comprehensive data that an LCA provides, it becomes much easier for builders to gain stakeholder acceptance (i.e. municipalities, homebuyers) because they have reliable data to point to when backing their claims for a building.
Options for Using an LCA
An LCA can be a daunting process. The factors that go into manufacturing even a single object are deeply interconnected, and a house is a complex system that’s built within a network of complex systems like manufacturing, resource extraction, civic infrastructure, transportation and many more.
Most LCAs are done by professionals, who have the training and software to be able to compile, interpret and compare data precisely.
Homeowners and home buyers can choose a green builder who can perform an LCA or hire a specialized consultant to complete one. Because of the resources involved in conducting a comprehensive LCA, this is probably best suited to new builds and significant retrofits.
If a homeowner or homebuyer is feeling ambitious, there are online tools and databases available that can support people in conducting their own LCA. A few key resources are listed at the end of this post.
Home builders, renovators and DIYers can also use the LCA data provided in environmental product declarations to help choose building products that align with their building priorities (e.g., low emissions, responsible water use, low waste, etc.).
And finally, anyone could conduct a more abstract LCA before the start of a building project if they didn’t want to wade through data. You certainly don’t need a degree to think more holistically about a home.
In fact, the nonprofit organization RE Sources has this cool lesson plan for high school students that asks them to evaluate the lifecycle steps of a single product they own based on questions ranging from what resources were extracted to create the product to how long it will last in a landfill.
It’s not a precise evaluation of that product, but it’s a useful exercise for those who want to shift their building decisions towards cradle to grave, or even cradle to cradle thinking.
Resources for Conducting an LCA
The U.S. General Services Administration has a Sustainable Facilities Tool that walks you through how to conduct a Life Cycle Assessment.
Life Cycle Assessment of Buildings: A Practice Guide, from The Carbon Leadership Forum, is an in-depth introduction to LCAs that offers additional online resources and tools.
Building for Environmental and Economic Sustainability (BEES) offers a free online tool that compares the environmental performance data of over 200 building products.
The National Renewable Energy Laboratory created the U.S. Life Cycle Inventory Database to help individuals with environmental accounting.
Feature image: Manuela Adler; Image 1: Gianmaria Saccenti
