The 2,560-square-foot main level has an open floor plan, with the public areas—great room, kitchen, and dining area—at its core. On the periphery are the private zones—bedrooms, baths, and an "away room," where Nathan plays the piano. The 2,900-square-foot basement is fully finished, with a family TV room, game room, exercise area, additional bedroom, and a storage area. Making full use of a home’s square footage is just one way Ken conserves energy.
The home was built with insulated concrete forms (ICF), which shield the house from outdoor temperatures and buffer noise. ICF are large foam blocks that are stacked to form the house’s foundation and outer walls. Concrete is poured into the blocks to make extremely strong and airtight walls. "The problem with typical 2x6-stud-wall construction is that every stud is a way for cold to get through; it’s a thermal bridge," Ken explains. "With ICF there are no thermal bridges." From a healthy home aspect, the ICF walls do not support mold growth and are formaldehyde free. The walls also are fire- and insect-resistant.
"Concrete’s greatest green or sustainable contribution lies in its durability," Ken says. "It’s going to be there for 100 years unless someone tears it out." And when it is torn out, it’s recyclable. "It can be ground down to make more concrete. It’s not a landfill issue," he says.
Ideas from the Dahlins’ kitchen:
• An in-floor hydro-heat system that warms the house is divided into zones, so rooms can be heated at different levels simultaneously.
• Dual refrigeration from SubZero—separate compressors for the freezer and refrigerator—keeps foods fresh longer and prevents the exchange of odors between compartments. Air- and water-filtration systems eliminate bacteria and impurities that can affect foods, ice, and water. The 42-inch-wide appliance runs on less energy than that required to power a 100-watt lightbulb.