Consumers have heard for years that solar, wind, and geothermal power might soon cut their monthly energy bills. But things get exciting, even exotic, looking a decade or two ahead. Scientists envision that light bulbs will talk to switches, furnaces to windows, and everything to the Internet. Homes generate their own power in basement plants. Windows and paint change color to harvest sunlight or reject it.
But it's one thing for scientists to talk game and another for builders and homeowners to play. Cutting home energy use means changing consumer behavior and industry practice. "The construction trades are among the most conservative out there," says Leon Glicksman, a professor of building technology at the Massachusetts Institute of Technology. It's also a highly fragmented, diffuse industry of mostly small contractors installing separate systems in a home. One does heating, another lighting, a third the electrical system. There often is nobody who integrates the many systems with an eye to energy savings.
So as much as scientists like to talk whiz-bang for the future, what's also needed is training. "It'll be interesting to see 10 or 20 years from now how much progress is technology oriented and how much is education based," says Dariush Arasteh, who studies building technology at Lawrence Berkeley National Laboratory.
That said, promising new technologies are emerging in labs, and some in commercial buildings, that in a decade or two could win over even the most skeptical builders and homeowners.
Tunable tints. In most U.S. climates, there is no easy answer when looking for energy-efficient windows. Today's panes tend to be specific to a type of weather—glass can be treated to reflect sunlight for warm-weather areas or not reflect it for colder climes. "If you're in St. Louis, you ideally want one in summer and another in winter," says Arasteh, whose lab studies window energy use.
Intense research is focusing on smarter windows that can change their coating on demand. A tint could block the sun in hot weather but fade on cold days to let in warm rays. Special "electrochromic" coatings darken when a small voltage is applied. A Minnesota company, Sage Electrochromics, already sells early versions that are used in some high-end homes, usually as skylights.
At current high prices, they make more economic sense for commercial buildings. Factories and offices could reduce daytime lighting costs with more windows but can't afford to let in the sun's heating rays. Homes tend to need more of their light at night and benefit less from natural illumination.
Still, commercial sales can help fine-tune production to get costs down. Then the entire window-producing industry must revamp itself for the new tech, an issue that has held up other energy-saving approaches, such as triple-pane windows. "It's like having a factory that's set up to make simple sandwiches," says Arasteh. "Now you're asking them to make club sandwiches. These changes take years."
Smart homes. Existing home heating, cooling, and lighting systems could save energy with some new smarts. Lights typically don't know they can turn off or dim when the sun comes up, and air handlers continue blowing heated or cooled air at open windows. Simple networking that got all of them talking could wring out a third of energy use in a building, says Neil Gershenfeld, an MIT computer science professor: "It's sort of an Internet of things."
Many companies have tried for the smart home. About 20 different families of gear already exist. But they're not made to work with one another, and none can expand to handle complex systems while being cheap enough to work with a simple light bulb. Gershenfeld's lab has developed a simple networking language—think Morse code—that can turn a light bulb into a node on the Internet, sending and receiving data. The same code could control complicated heating and cooling systems that respond to outside temperature changes, or as people come and go.
Prototypes already exist of hardware that a homeowner might install cheaply, even in an existing structure. One attraction: "We don't have to rewire the whole building," says Charlie Catlett, chief information officer at Argonne National Laboratory, which is installing an early test of the system in one of its buildings. Plus, "these things are so cheap and small that we can actually think about putting them into things like chairs and light bulbs."
Frozen smoke. Nothing is weirder than the aerogel that might one day keep our homes comfy. One of the lightest solids known to man, the translucent and wispy material looks like a slice of solid smoke. It's about 99 percent gas trapped in nano-size bubbles within a lacelike material, and there is no better insulation for a given thickness. "The problem is that for now it's expensive as heck," says Andre Desjarlais at the Oak Ridge National Laboratory.
But breaking into the construction industry, which uses nearly two thirds of all insulation produced, is a priority for the few small companies commercially producing the ethereal stuff. "We're focused on those areas where space is at a premium," says Aspen Aerogels CEO Don Young. That means retrofitting existing structures, particularly older masonry walls with no hollows for stuffing conventional insulation. Public partners are helping to pay to install aerogel insulation in more than 250 New York City housing units as an early test. For now, though, aerogel will largely remain a tool for space agencies, the Pentagon, and oil companies that can pay the steep premium.
Desjarlais's lab at Oak Ridge focuses on technology to secure the building "envelope" for energy efficiency. It includes a number of bizarre-sounding technologies, such as paint that's white one minute to reflect sunlight and later darkens to collect it. But nothing can top the weird nature of frozen smoke.
[Read how a geothermal system can cut heating and cooling bills.]
Home hydrogen. Fuel cells have powered space flight for decades, and auto companies hope they'll soon be ready for cars. In a decade or two, they should be commonly available for the basement, says Tom Drennen, an associate professor at Hobart and William Smith Colleges and coauthor of Pathways to a Hydrogen Future. "There's a lot of efficiency in generating electricity where it is used," he says.
Fuel cells generate electricity through a chemical process that combines hydrogen and oxygen. When the inputs are pure, the only side products are water and heat in a process that's long been perfected. "What's not perfected is getting the fuel, the hydrogen, to them," says Branko Terzic, a Deloitte consultant on energy policy.
A few Japanese companies have installed experimental models in homes that run off natural gas. An added device strips hydrogen from the gas to fuel the cells, which generate electricity and hot water. A smaller slice of American homes have gas service, limiting that approach here. Converting natural gas also produces greenhouse gases. But the process is still less polluting than traditional electrical generation. "And nothing's wasted getting it to the home," Drennen says.
Brighter bulbs. Here's a twist on the old joke: In a few decades, nobody will know what it even means to change a light bulb. "The house will get torn down before a light bulb ever burns out," says Russell Dupuis, a professor at the Georgia Institute of Technology and fan of light-emitting diodes, or LEDs.
The 130-year-old Edison bulbs will first get replaced in the home by compact fluorescents, which use about a third the energy and last years longer. Even more miserly LEDs are expected to later replace fluorescents. LEDs use about 12 percent the energy of incandescents and can last 50 years or more.
They've already become popular in some commercial settings, particularly where lights burn 24-7—such as the freezer at an all-night Wal-Mart. Steep initial costs limit their appeal to U.S. homeowners. People just can't embrace spending $120 or $130 on a bulb. While even that steep price can earn a payback in eight or 10 years, it's too long for the typically nomadic U.S. homeowner. Dupuis dreams that people soon will ask whether a prospective home has LED lights and will pay more for one that does. He should—he built a passel of them into his house.
[Read how LED lighting for now remains a tough sell.]