Green Icon is a Zero Energy Building. (NOW No Watt) The annual energy consumption proves this result: EPtot = 0,00 kWh/cubic meter (per year); the building reaches the energy class A+. The first Green Icon unit is placed in the new “Bioenergie” establishment in Mantova. In this wood-unit are accommodated the control station, the auditorium, the archive and all staff’s services. This unit is all realized in wood technology: main walls are designed in “Legno-Tec”, made from multilayered X-LAM (fir-tree) panels. Thermal and acoustic insulation is realized in wood fiber layers. The use of ecological materials and the technical systems installed make Green Icon a reference model of energy efficiency building. The wood-units can be realized in three different sizes, 40- 80 -120 square meters, and joined to form a complex of various dimensions. The time required to build a 40 square meters unit is only 30 days.