ONLY a few years ago "green" architecture was regarded as interesting but quirkily "right on."

Today it is mainstream. Witness the Queen's Award For Enterprise conferred on Eco Arc, the international award-winning ecological architectural practice in Harton, near Bartonle-Willows last April.

After 16 years of new builds, conversions, housing leisure and health buildings which became energy-efficient units producing their own power and water, architect Andrew Yeats, founder of Eco Arc Design Consultancy, was finally blessed by the Establishment.

Now the kind of homes he has always advocated and demonstrated will be the norm not of the future, but the very near future.

New environmental regulations set to take effect within the next three years will dramatically change how commercial properties are valued, according to property consultants King Sturge.

New regulations issued by the Office Of The Deputy Prime Minister will place a major new onus on property owners, occupiers, investors and funders, linking a property's value to its green credentials, says Simon Cullimore, of King Sturge's Valuation Department in Yorkshire Building Regulations Part L and Energy Performance Of Buildings Directives, were due to take affect at the start of last year (2006) but have been delayed due to a shortage of experts needed to carry out the work.

When they are introduced, they will include Energy Performance Certificates through which all buildings built, sold or let will be rated for energy efficiency and CO2 emissions on an A - G scale.

Mr Cullimore, a partner, says: "These regulations are part of a growing number of legal and regulatory changes created as a result of concern over the environment, climate change and the need for sustainability.

"Over the past few years, our Government has committed us to many international environmental agreements. Almost 50 per cent of the UK's carbon emissions are generated through the way we heat, light and use our buildings.

"For this reason, property and construction have been identified as key sectors in delivering these commitments and these regulations are an early example of new legislation being introduced to ensure that property owners, managers and occupiers start to move in the right direction."

Under the new regulations, every commercial property, new or old, will have to carry, in effect, its own energy efficiency label, similar to that on domestic white goods.

Mr Cullimore says: "It is important that all property developers, funders, investors and owners start to consider this now, as it will have a significant impact on property valuations.

"A poor energy performance rating is likely to have a significant negative impact on a property. Government occupiers and business tenants which value their green credentials, are likely to be more attracted to the best-rated buildings."

He warns that large investors, including institutions with a duty to their trustees and shareholders, are also likely to shy away from inefficient buildings.

He adds: "A fall in occupational and investor demand could result in a decline in values for outmoded, inefficient buildings and lead to a two-tier property market.

"If this happens, it will create, for the first time, a link between the value of a commercial property and its green credentials. This challenges the current view that green buildings provide a questionable advantage and are, more expensive to build and maintain."