Here, homes are evaluated against a minimum standards for energy and water usage and are rated from one to six stars based on how they meet the requirements in nine different categories.
[4] In Wales, advice on and access to sustainable building is available from a not-for-profit organisation called Rounded Developments Enterprises.
It is a zero-emission structure built on the previous Ovaltine egg farm and features its own 225-kilowatt wind turbine and photovoltaic array, capable of 3,200 kilowatt-hours per year.
[6] There is also the case of the BowZed building in east London, which made it to The Guardian's list of top eco-building.
About 90 percent of its electricity is sourced from solar and wind power while a wood pellet-powered boiler provides hot water to the residents.