How long ago it seems, the time when eco-buildings were regarded as the preserve of well-meaning tree-huggers, probably living in yurts in Wales, who were considered mostly harmless but best given a wide berth, just in case. We’re all tree-huggers now, including hard-nosed big business.

It’s not just because we want to save the planet that buildings and the people who produce them are going very green indeed. It’s not just because ever-tighter government regulations are moving us inexorably towards low-carbon buildings, surprisingly rapidly. It is because of a sea change in the attitude of the business community.

Companies now realise that it is commercial suicide to disregard the environmental consequences of their actions – customers won’t allow it. As a result, there is something of a greener-than-thou race going on.

There is a remarkable sight at the BRE Innovation Park, Watford: six prototype sustainable homes of the future, some nearing the holy grail of being zero-carbon – a combination of thermally efficient design and materials, plus technologies such as solar panels and biomass boilers, can reduce net CO2 emissions to zero. BRE (Building Research Establishment) is a commercially run organisation, and the six homes have been privately produced by commercial firms. Significantly, one of the greenest is by megahousebuilder Barratt. The prototypes indicate that there is serious environmental thinking going on in boardrooms.

Fossil fuel energy prices are on another of their sharp upward excursions. Whenever this happens, ingenious people find ways to mitigate the financial pain. The first mass-produced microcars in the 1950s, including the Mini, were a response to petrol shortages caused by the Suez crisis. The next big energy price shock, in the early 1970s, stimulated the first wave of eco-buildings and made everybody careful about leaving lights switched on.

Money talks, and the commercial case is now extremely strong. Rising fuel bills are stimulating fresh thinking about the built environment, for the simple reason that companies want to reduce their overheads. Buildings with low running costs are now, more than ever, an attractive proposition. If you’re still occupying – or planning to build – a property with high-energy consumption, you’re in trouble.

“Poor energy performance is a ticking time bomb for those lumbered with the wrong type of buildings,” ran the blurb for a recent London conference highlighting “the unsustainable office”. It is the kind of conference that panicky property professionals are flocking to.

If your rivals are in a state-of-the-art eco-office, and you’re in some thin-walled, fully air-conditioned dinosaur building, they’ve got a head start on you, costs-wise.

So what’s best practice? A few years back, I asked Britain’s most successful architect, Norman Foster, whether it was technically possible for a skyscraper to generate all the power it needed to run itself. Yes, he said, but it would be very expensive to build. Today, the costs are falling, and Foster is one of the world’s top eco-architects, picked to masterplan what is billed as the first zero-carbon, zero-waste city, Masdar in Abu Dhabi. The oil-rich emirate is looking to the future, and is prepared to sink a lot of its wealth into ultra-sustainability. It will use the sun and wind instead of oil at Masdar, and public transport will be powered by electricity.

What about our existing cities, with their huge carbon footprints? Paris is set to have a world first: an office complex that will produce more energy than it consumes. The Energy+ is designed by the American architectural powerhouse SOM, also responsible for the world’s tallest tower, the Burj Dubai. The Paris building will, by contrast, be low and compact, with many wings and courtyards. It will generate 20% more power than it needs – from wind turbines, solar heat collectors and photovoltaic panels, and by using the ground to store excess heat (offices generally need cooling more than heating). The excess electricity can be sold back to the French national grid. Another bonus is that working in a better environment leads to greater productivity; “enhanced competitiveness for business” is how the architects see it.

Two former SOM architects, now operating independently, are also taking forward the environmentally conscious way of building. Adrian Smith and Gordon Gill designed the Pearl River Tower in Guangzhou, China, an office skyscraper originally planned to be zero-energy in use (it deploys renewable energy sources to achieve a net consumption of zero). In practice it won’t quite reach that, because the Chinese authorities wouldn’t allow it to include an eco-power plant. The tower is under construction, and meanwhile Gill and Smith are working on another “positive-energy” building, for zero-carbon Masdar. It will contain offices and flats. Clearly, green consciousness is spreading.

You see something of this attitude in the UK, where everyone from housebuilders to high street chains are beginning to appreciate the business benefits of a proper environmental policy. There is, however, one big change required: people need to work much closer to their homes, or at least to ensure that home and work are close to good public transport. That’s an issue housebuilder Berkeley Homes is addressing in its “sustainability commitments”. “About 90% of our developments are within 500 metres of a public transport node,” says the company’s Karl Whiteman.

Berkeley provides evidence that mainstream housebuilders are accepting the business case for going green. The company has largely switched from greenfield suburban estates to “brownfield” land – town and city sites formerly used for, say, factories or hospitals, with good public transport links. It is also designing homes that use 30% less water and has cut its own carbon emissions as a company by 20% since last year. Its website includes an interactive tool offering tips on saving resources and money around the home.

“Some of our newest developments have combined heat and power plants,” Whiteman continues. “These make use of the heat produced by power generation and are up to 25% more efficient than taking power off the national grid. We’re running two years ahead of the government’s suggested energy-reduction timetable.” www.berkeleyhomes.co.uk