Sorting through the "greenwashing" can be an onerous task these days, especially when it comes to residential construction.
Rather than have a set list of questions to try to catch prospective contractors greenwashing I think it would be far easier to cull out the impostors by simply asking open ended questions and allowing them to expose themselves (figuratively of course).
I always like to hear fellow professionals describe to me what "green building" means to them. You can usually get some idea of how serious they are about green building by how they answer that question.
Look for answers that include at least some form of the following categories of green building.
Sustainability: How sustainable are their practices from deconstruction to material selection to application techniques. Do they use FSC (Forestry stewardship council) lumber? Do they have any idea of how the materials they are putting in your house will be disposed of once they have come to the end of their useful life?
Energy Efficiency: see how they talk about energy efficiency. Do they only mention solar panels and energy star appliances or do they actually analyze how your home will perform as a system including the building envelope, insulation, air sealing, systems and people.
Cost: Do they have a good command of the cost of various systems and materials and what the cost/benefit trade off is? Do they understand the upside of paying more for certain green materials and can they verbally justify this to you?
Durability: Do they talk about durability as a key variable in green building? If not, ask them why how long something lasts is not important in considering sustainability. I find that this is the first area that a true greenwasher will miss.
Health: This is by far the most important element to most of our clients. Can the contractor explain clearly what issues arise with indoor air quality and what steps they take to ensure that your home will be healthy, especially if they understand how to build a home "tight" so that there is no natural ventilation.
In fact, ask them how they intend to get you and your family fresh air. If they mention ventilation techniques like Heat Recovery Ventilators (HRV) or Energy Recovery Ventilators (ERV) then they likely have some experience building tight properly ventilated buildings.
Most importantly, make sure that the areas that your prospective contractor talk about and focus on are indeed the things that are important to you and your family. If you are hypoallergenic and are worried about your indoor air quality and all your contractor can talk about is solar panels, then it is time to move on to the next candidate.
For more information: