Green Definitions

Carbon Footprint: An estimate of how much carbon dioxide an entity (be it person, family or building) produces and releases into the atmosphere (the EPA has a personal calculator). The resulting figure is used to buy carbon offsets (see definition) or engage in ameliorative activities such as planting trees.

Carbon Neutral: Reducing energy use and compensating for the amount of carbon dioxide an entity generates through either obtaining energy from renewable sources or offsetting.


Greywater and Blackwater: Both are waste water, but the former is generated by washing dishes, laundry and bathing while the latter is generated from toilets and contains much higher levels of bacterial pollutants. According to the USGBC, greywater “makes up 50-80 percent of residential wastewater” and can be recycled for irrigation. New residential systems redirect it for use in toilets.

Passive Solar: This refers to capitalizing on the warmth and light of the sun with simple strategies instead of complex technologies, such as the use of windows and heat-absorbing and/or reflective materials as opposed to heating and cooling systems.

Photovoltaics: A solar power technology that uses cells, panels or arrays to convert light from the sun directly into electricity.

Solar Thermal Panels: A device that collects energy from the sun and coverts it into heat for domestic water systems and/or space-heating systems.

Rapidly Renewable Materials: Resources that can be rapidly replenished as they are used, such as some woods, grasses and cork.

Zero-Carbon Buildings: There are no emissions of carbon dioxide at all from any of the systems and appliances in these structures.

Zero-Energy Buildings: These structures incorporate systems to both generate and conserve energy, so net energy consumption over a period of a year is zero.