For centuries, mankind has made do with finding shelter between walls and under a roof. Ostensibly, for all of the advances in stability, height and - thanks to computer-aided designs of late - flashiness, buildings have retained fundamentally the same purpose since. But now, some suggest, an architectural revolution is afoot, as different disciplines come together to make buildings "smart" or "intelligent".
"Building owners are having to adapt to technology that wasn't available just five years ago," says Jim Sinopoli, architect and founder of Smart Buildings, a Texas-based leading practice in this new field. "And that's going to change the way we approach building. The question will be how design engineers and architects respond. Making buildings smart will be disruptive. But it's inevitable."
Indeed, while smart or intelligent buildings have yet to settle on one definition - it encompasses using technology to improve control and communications, and to maximise performance and efficiency - according to industry analysts IDC Energy Insights, worldwide companies spent US$5.5 billion on such buildings, new or retrofitted, in 2012. By 2017, that figure is projected to top US$18.1 billion, with other reports citing much higher estimates.
China now has its own annual Smart Home and Intelligent Building Expo. Certainly, much as other elements of our environment - from our personal devices to our home interiors and vehicles - are becoming more intuitive and automated, so can we expect the same from buildings, from how they are run to how they are built. And, as with our hi-tech gadgets, cars and the like, in part this is simply a response to buildings' growing complexity, such that, as Sinopoli puts it, "every aspect of building is increasingly being penetrated by IT".
The human element is a key factor behind the drive to innovate and improve. As Sinopoli says, "while smart architecture is about making buildings cheaper and greener, it's important to recognise that it's also about making them better for their occupants" - in terms of lighting, ventilation, sense of space and safety.
For example, a smart building might shut off gas lines, close down computers and notify occupiers in the event of an earthquake. And Deloitte's new corporate headquarters in Amsterdam, called The Edge, has 28,000 sensors micromanaging humidity, light and temperature to make employees feel as though they are outside on a pleasant day.
Even neuroscience is being brought into the mix in a bid to understand how the brain reacts to certain environments, and then using that feedback to help determine building design. Studies have shown that brain function is improved by visual access to natural light and vistas of the sky, trees and landscape; positive feelings have also been measured in response to curves over straight lines.
"You need to steer the question of intelligent building more towards how it can have a positive impact on the people who use that building," says Betsey Dougherty, co-founder of Dougherty + Dougherty Architects in California, an executive member of the pioneering Academy of Neuroscience for Architecture and an expert in using smart architecture in schools.
"Something as subtle as the colour of the walls, the acoustics and reverberation, glare - all these affect the quality of life inside a building. A smart building should allow you to get better faster if it's a hospital, learn more if it's a school, be more creative if it's an office. Of course, buildings will get generally smarter as cellphones do - that's to be expected. But we have to raise the bar on the idea that a building is essentially a box."
The technological advances are staggering. Analytic systems that allow continuous data mining from wireless sensor systems, for example, not only help faults to be found, but also decide which ones should be fixed first - optimising their functionality and reducing energy wastage and running costs. They also provide insight into what the energy usage and costs are in immediate detail, so building owners don't have to wait for the bill to arrive.
Sinopoli cites the Microsoft campus in Redmond, Washington, with 200 hectares encompassing 30,000 pieces of mechanical equipment and requiring seven building management systems. Smart buildings integrated the lot into one database. Bluetooth-based indoor positioning systems can identify how many people are in a building and where they are, again allowing for adjustments that save energy.
The technology has moved to exteriors in recent years, with progress in the development of "smart façades". Chemical company Alcoa has developed titanium dioxide tiles that filter the surrounding air and destroy pollutants - they've been used to create a skin around the Torres de Especialidades, a new Mexico City hospital. Bloom is a thermal bi-metal shade that curls in reaction to a certain heat level, allowing more air to pass through it, and closing again when the temperature cools. And building engineering giant Arup is testing a façade impregnated with millions of microscopic algae plants that absorb sunlight to heat water, which can then be harvested for use in the building.
Combinations of various materials technologies also advance the idea of tomorrow's smarter building - for office blocks and specialised facilities at first, and later for residential ones. Photovoltaic cells, for instance, can now be embedded into glass without any noticeable effect on transparency, and they can also be incorporated into concrete. The result is a building that can generate its own power, with little loss through transmission.
Nano materials - having escaped the realm of the shape-shifting buildings envisioned in a more sci-fi future - will soon offer the benefits of being super-light but super-strong, leading to thinner, perhaps transparent façades that could rewrite our conception of the inside/outside divide. A nano composite steel - three times stronger than conventional steel - is already on the market, as is nano-based self-cleaning glass and smog-eating concrete.
The fact that such technologies are coming into the market now is why "we can expect this sort of idea to become more prevalent", Sinopoli says. "If you have to put in a curtain wall and can put in a photovoltaic one for not much more money, building owners will demand it."
While smart building is still getting off to a slow start, designers are satisfied that they have proof of its value, which will eventually drive high demand for the technology.