Using technology developed at the University of Maine, a Newton company is pursuing a simple enough idea: Why not turn cardboard boxes used just once into the fluffy cellulose insulation that is blown into the cavities of leaky old homes to make them more comfortable and cheaper to heat in winter?

Most of us toss those cardboard boxes that bring goodies from Amazon, Best Buy, and other retailers into the recycling bin without a second thought. But the cardboard may soon be coming back in the form of a cozy blanket of insulation lining the inside walls of homes around the country.


"Recycled corrugated cardboard represents a fantastic opportunity," said Mark Brandstein, chief executive of the Newton startup, UltraCell Insulation. "There's a big demand for green, recycled materials out there."

UltraCell was recently awarded two large grants from Massachusetts and federal agencies and is testing its technology to treat recycled cardboard with fire-retardant chemicals that will make the material safe to use as insulation, and slightly more energy-efficient than traditional paper-based cellulose.

Cellulose materials make up only a fraction of a $7 billion insulation market in North America, and nearly all of the 500,000 tons of cellulose insulation made today is from recycled newspapers. However, the growing environmental movement is boosting sales of cellulose by about 15 percent a year, Brandstein said, double the rate for insulation made with fiberglass or foam.

But the supply of newsprint that can be recycled is falling because fewer people are buying newspapers. Cardboard, on the other hand, is on the rise, thanks to the boom in online commerce.

"There needs to be another recycled cellulose insulation product out there to fill the gap, and we believe we have it," Brandstein said. "We believe we're ahead of the trend."

UltraCell believes it has solved a problem that has kept most cardboard from being more widely used. Old boxes carry contaminants such as glue, tape residue, metal staples, and other non-paper materials that make it more difficult and expensive to convert into insulation.


UltraCell recently made an 18.5-ton batch of chemically treated cellulose at Crocker Technical Papers Inc., a Fitchburg paper mill that dates back to 1860. The rolls of cellulose were subsequently mulched into fluffy insulation by a Pennsylvania mill. The material will undergo laboratory and field tests this fall, and if successful, could be available commercially next year.

The year-old company has received a $100,000 grant from the Environmental Protection Agency and $40,000 from the Massachusetts Clean Energy Center. Alicia Barton, the center's chief executive, called UltraCell's manufacturing process "an interesting and exciting technology" that could boost recycling and improve home energy efficiency, with the added benefit of generating business for paper mills.

The technology was developed and tested at the University of Maine, where researchers came up with a unique "wet" process of separating contaminants from cardboard and adding a proprietary mix of borate chemicals to make the material fire retardant, Brandstein said.

The university owns the key patent jointly with UltraCell. Brandstein is a former telecommunications executive brought in to grow the company, which was founded by a group of academics, industry officials, and corporate executives.

Recycling newsprint into insulation is a dry process that involves sprinkling fire-retardant chemicals on the finely shredded fibers. The wet process pulps the cardboard into a slurry mix, at which point glues, tapes, metals and other materials are removed. The company's fire-retardant chemical mix is then added. That ensures a "more consistent and thorough" application, Brandstein said.


After it is dried, the pulp is ground into a fluffy mulch and packaged in 25-pound bags.

Brandstein expects such insulation to cost about the same as that from newsprint. Still, cellulose insulation has a long way to go to be competitive price-wise with fiberglass, which remains the most widely used material for building insulation.

It costs about $6,500 to insulate a 2,000-square-foot home with fiberglass, said Chris Kirouac, a sales manager at Pro Insulators in Berlin and New Bedford.

Cellulose is more expensive — about $12,000 per home — but generally has higher insulating value than fiberglass, Kirouac said. Foam insulates best, but is so much more expensive — three to four times the price of fiberglass — that it is not as widely used in New England.

As for UltraCell's prospects, Kirouac said his industry "welcomes all new technologies, as long as they work and are priced right."

Charles Cottrell, vice president at the North American Insulation Manufacturers Association, said cellulose is not as environmentally friendly as its boosters claim. His group represents makers of fiberglass and spray-on foam insulation.

"It's not as green as people think," Cottrell said. "If you measure end-to-end how much energy it takes to make corrugated cardboard and then the entire recycling process, it's not that great."

Brandstein countered that the biggest environmental benefit of cellulose is that it uses recycled materials that otherwise would end up in landfills or incinerators.


"I don't know how you can get any greener than that," he said.

Though UltraCell's primary goal is to make affordable, environmentally friendly insulation, it could also help struggling paper mills, which have been hit hard by fierce foreign competition and a digital society that uses less paper. A century ago, New England had hundreds of paper mills, but that number is down to fewer than 50.

"There are a lot of paper mills that want to partner with us," Brandstein said. "We're talking to many mill owners across New England and even the mid-Atlantic states. This could really help their business."

The company has been scouting paper mills in New England and upstate New York as possible production sites.

"It's certainly an intriguing product," said Don Brutvan, vice president at Crocker Technical Papers, owner of the Fitchburg plant that helped produced the first batch of recycled cardboard. "It looks like a great niche product, but we'll have to see if it fits the mill's long-term capabilities."