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.