Though built near Chicago, where temperatures can plummet below zero in the winter and exceed 100° F in the summer, the 430,000-square-foot warehouse of Roman Inc. has no heating or air conditioning units. Yet the temperature in the warehouse stays about 70° F year round. The key to the building's stable year-round temperature is a special concrete and polystyrene wall system called Solarcrete.

All exterior walls of the warehouse are 12 inches thick, with 7 1/4 inches of expanded polystyrene sandwiched between 2 3/8-inch-thick layers of shotcrete. The walls are buried 3 1/2 feet into the ground, below the frost line, and extend full height from the footings to the roof, without any joints or breaks that could let air enter. The only elements penetrating the 7 1/4 inches of insulation are galvanized-steel web ties, but these ties are thin and any thermal transfer across them is negligible. The metal-deck roof is covered with two layers of polyisocyanurate insulation over which a rubber membrane was applied. Thanks to the large amounts of insulation, both the walls and roof each have an R-value of 35. "Essentially, we've constructed a one-piece ice cooler that's settled into the ground below the frost line," says Tony Jedlinski, executive vice president of Roman Inc.