|| The Advanced-Efficiency Approach or Ultra-Low-Energy Buildings (ULEB) is a further development of a Low-Energy Building, requiring up to 90 % less primary energy consumption than a conventional new building. The Ultra-Low-Energy Building maximizes a building’s energy efficiency potential. An Advanced-Efficiency Approach is needed to attain these low levels of energy consumption. Ultra-Low-Energy Buildings set more ambitious energy efficiency standards, using the most-energy-efficient components and systems available to reduce the energy consumption. This energy consumption should preferably be covered by renewable energy sources such as solar energy, ambient and geothermal energy, sustainable biomass etc. It can be cost-effective, depending on the trade-off between incremental capital costs and long-term energy cost savings but this may not always be the case.