Building Green By using the most current building and energy technologies in combination, GBCC clients can achieve true sustainability in home design. For example: Insulated Concrete Forms (ICF) replace conventional framing. The forms also serve as interior and exterior insulation, yielding a high "R" value. Geothermal heating systems utilize underground temperature—which remains constant year-round—to warm the building in winter and cool it in summer. Photovoltaic Cells can generate enough electricity to operate, among other things, the geothermal system. Masonry Heaters require far less wood and burn cleaner than traditional wood stoves. Salvaged antique building materials and architectural elements are aesthetically pleasing and offer an opportunity for home recycling.