Knowing what is and isn’t a truly “green” purchase can be a challenge. Luckily, product lists from EPA, DOE and USDA have placed guidance for environmental and energy attributes. There's something called the Green Procurement Compilation on the sustainable facilities tool (sftool.gov) by the GSA which organizes product and service requirements from different sources and can be used to identify which environmental programs apply to specific products. Hope this helps!

That would depend on which "green" certification standard you are building towards. If you were actually building towards benefiting the environment, you would have to look a the carbon costs of all the components but building "green" isn't about actually benefiting the environment, like organic foods, it's about meeting an arbitrary set of specifications an organization has set up and paying for the inspection and certification.

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