Green Material Choices
Material choice is often the first thing people think about when undertaking a green building project. Visions of bamboo flooring and countertops made of recycled material may come to mind. But, to truly build green, consider your design and green goals before going shopping for that green product. The greenest choice is the one that performs best for your design and use. Remember that a material can be green both by its manufacture and by its performance after installation. Many materials may seem like good choices, but should be scrutinized thoroughly. The best methods for green products assessment consider a product’s benefits in place, along with its environmental cost for manufacture, maintenance, disposal, and replacement. In other words, consider a full Life Cycle Assessment (LCA).
A typical LCA should examine the environmental impact of the product from the (a) raw material, to the (b) manufacturing process and transportation, to (c) construction and use, and the end of the products useful life (d) reuse, recycling and disposal.
Another measurement of how green a product might be is by its embodied energy, also referred to as its ‘carbon footprint.’ We often refer to some products as sustainable because the raw product is from a sustainable agricultural or manufacturing process, but is shipped halfway around the world to be incorporated into our project. Products made from recycled steel are a good choice but when compared to wood, which has the greater embodied energy? The energy to grow the tree is solar energy.
Materials can be “Green” for a number of reasons. Attributes that make a material green can include one or more of the following:
• Help Reduce Energy or water use in the home — Often materials are considered green because they save energy, such as CFL light bulbs or insulation products. Note that their manufacturing process or ingredients may not be environmentally friendly themselves. These products’ benefits must overcome the environmental penalty from their manufacture to be truly a green choice. Choose fixtures and appliances that use the least amount of water possible. These products often also save energy directly (reduced appliance draw) and always save energy indirectly (reduced water use saves energy by lowering energy needed for water treatment and pumping).
• Be manufactured in an environmentally friendly way — This is the most common method by which products are marketed as green. There are many attributes to consider, but a few examples are:
• products that are made of recycled or salvaged material (a high percentage of post-consumer recycled content is best when considering recycled products)
• products that are made in an energy efficient manner or are made with renewable energy
• products that are not manufactured from environmentally dangerous components or processes (such as petroleum, chlorine, vinyl, tropical wood, etc)
• local products; Not just food, but building materials or bio fuels too.
• natural products; products that require little modification from their natural form.
• materials from renewable sources (bamboo or wheatboard, for example)
• wood products carrying a third party certification that they are responsibly harvested. (FSC)
• Help Contribute to a healthy indoor environment — These products include low/no VOC paints, finishes, adhesives, caulks, and also carpet products. Wood products such as cabinetry and furniture or plywood products that do not contain added urea formaldehyde are also smart choices. HRV’s and ERV’s, and high performance filtration and humidity monitors on HVAC systems are a best practice. Simpler examples are window shades.
• Be Durable — A product that performs well for a longer duration than the standard, or does not need costly maintenance, will not need to be replaced as quickly. The choice of a product with a longer lifespan or interval between maintenance will reduce energy consumption needed for upkeep, disposal, or manufacture of a replacement.
• Be Regenerative — A Product or system that helps to repair or benefit the environment in which it exists. Most of the time this particular attribute is implemented as a systems approach through integrated design. Examples of a truly regenerative material are harder to point out, but may include landscape stone that allows water to penetrate the soil below, or lumber sawn from downed trees or trees thinned from a dense stand or dangerous location. A “living wall,” or plant matter, may provide needed humidity to an indoor environment, while also producing healthier air, is another example.
• Look For — Any opportunity to reuse existing materials or reduce your consumption of new materials. Wherever possible, recycle your construction waste.
• Avoid-Products that make unsubstantiated “green” claims, products that have reduced durability, flashy products that do little to reduce energy use, or products that cannot be recycled at the end of their life cycle.
Materials to consider to be incorporated into a new home project could include: Foundation system; Insulation; Lumber and Roofing; Windows; HVAC equipment; Plumbing fixtures; Light fixtures and Appliances; Flooring and Tile; Doors, trim and Cabinetry; Drywall and Paint.
• Remember that a product that saves energy in its use is probably a better choice than a product that saves energy during manufacture. A home may be built almost entirely from “green” products but not be green at all. Integrating green products into the design is part of the holistic approach to sustainable building.
Other topics to be addressed in this series will include energy, heating and cooling, indoor air and environment and solar power.