Strict thresholds for reduction of carbon emissions, energy efficiency, decreased water consumption and use of more sustainable materials in new buildings take effect September 1 in Wales, whose Assembly Government adopted the first national green building standard in the U.K.

The policy, announced last week by Environment, Sustainability and Housing Minister Jane Davidson, mandates energy efficiency measures be taken in constructing new homes in order to cut the dwellings' carbon emissions by 31 percent compared to comparable structures built according to current regulations.

Under the new standards, proposed housing must meet Level 3 of the Code for Sustainable Homes, a six-tier system in which Level 1 is the lowest rating and Level 6 is the highest.

Non-residential buildings must meet the BREEAM "very good" standard as a minimum. The BREEAM rating system has five levels; pass, good, very good, excellent and outstanding. BREEAM stands for Building Research Establishment Environmental Assessment Method.

Key steps to achieve the ratings include improving insulation, reducing air permeability, use of a high efficiency boilers and installation of low-flow taps and toilets.