Serbian inventor Veljko Milkovic creates designs for eco-houses along with other energy-saving devices. Using passive solar design principles and earth-shelter techniques, he adds reflective surfaces below windows that unfold to capture and amplify solar gain into the home through the glazing; he also includes reflective surfaces under the eaves that help bring solar gain into the homes during winter. His self-heating eco-house – or Eko Kuca - building concept saves up to 85 percent on heating, 100 percent on cooling, 30 percent on lighting and about 20 to 40 percent on building materials, based on monitoring. The Eko Kuca is covered with a sod roof that sweeps up over the earth-bermed house to provide additional insulation for an energy-efficient envelope. In 2009, the Eko Kuca won a First Place Award for Serbia and Montenegro as part of the international Energy Globe competition for worldwide sustainability.