High-tech aerogels wrap homes with insulation

Aerogels are a high-tech material used in space missions. How about for insulating our buildings?

Aspen Aerogels, which makes insulating material for industrial applications, has started selling its air-filled aerogel blankets to make existing buildings more energy efficient, according to company executives. The company has done a number of installations in the U.K. and a few in the U.S., including a housing project in Rhode Island last year.

Aerogels are made by removing the liquid from gels, resulting in a material that is more than 90 percent air. The porous structure of that nanomaterial makes it difficult for heat to pass through. As a result, aerogels make very good and light-weight insulators.

Because of costs, aerogel manufacturers have focused on high-end industrial applications, such as insulating oil and gas pipelines and even the Mars Rover spacecraft.

But now, a handful of aerogel companies are offering thin blankets that serve as replacements for traditional fiberglass, foam, or cellulose insulation. It's still more expensive upfront but the costs have fallen to the point that it can make sense in certain cases, particularly masonry or curved walls, according to Aspen Aerogels.

"We opened a second manufacturing facility (in 2008) which gave us the capacity and cost structure to look at the traditional building insulation market," said Chris Blair, director of building and construction of Aspen Aerogels in North America.

Aspen Aeorgels says that its Spaceloft blankets have two to four times the insulating value per inch compared to fiberglass or foam. It's also relatively easy to work with, allows water vapor to pass through, and is fire resistant--a common demonstration of aerogels is to have a person fire a Bunsen burner below the aerogel while putting a hand on the top side.

Material company Cabot has also developed its Nanogel insulator for buildings. Another company, ThermaBlok, has had its insulation used in demonstration houses built during last year's Solar Decathlon home competition, where energy efficiency was a high priority.

Niche applications
Does that mean you should consider hanging aerogel blankets on your walls, floors, or attic to boost insulation? Not necessarily. The higher upfront still cost means that it's best suited for buildings with walls that don't have a cavity--typically formed by wood framing--that can be filled, said Blair.

The Rhode Island Housing Authority used Spaceloft during a renovation of a housing complex with 50 units in five brick buildings built in 1940s with no insulation. Contractors stapled the blankets of aerogel on the inside walls, screwed wall board on top of that, and then added a layer of plaster and paint. An advantage of this approach is that it wasn't too disruptive to people inside and added less than an inch to the interior walls, Blair said. The payback was just over five years when tax credits are figured in, according to Aspen Aerogels.

In other cases, contractors have used the material on superinsulated homes that are sealed from the outside, both over masonry and under shingles. On wood frame homes, thin strips of aerogel can be applied to studs to prevent what's called thermal bridging, where heat escapes through the walls' framing.

Aspen Aeorgels projects costs will come down but not dramatically in the next few years. Still, more stringent building codes means that the material can be a fit in more circumstances, said Blair. "Obviously, retrofits is the low-hanging fruit. As we get out feet wet, we're finding more applications new construction."