Energy - Use of energy-efficient building systems (i.e. lighting systems with occupancy and lux-sensors). Use of renewable energy sources (i.e. solar and wind energy). Use of a compact building volume and efficient use of glazing for reduced energy loss. Optimized building orientation towards south (northern hemisphere) to capture longer periods of daylight. Consideration of placement of glazed areas, to reduce solar gains in summer, increase in winter. Use of a building construction with a high thermal value that helps to passively cool and heat, reducing the need for technical installations. Use of water-saving toilets and taps- Provide leak detection. Use systems that allow water re-use and recycling. Use water in outdoor areas (close to building), to improve the microclimatic comfort during summer. Managing on-site rainwater through preservation of areas of ecological value and/or the use of absorbing surfaces like grass and plants. Use of materials with low embodied energy (materials that do not overly pollute during manufacture). Use of waste materials or material with a high percentage of recycled content in construction. Avoid the use of fragile materials that require frequent maintenance. Use of materials with hygroscopic value (materials that regulate and improve indoor comfort). Use of certified materials. Ask for EPDs (environmental product declarations) to understand where products come from. Create environmental stations throughout the building to sort recyclables and dispose of waste. Require waste management during construction to limit the impact on the environment. Provide facilities for composting organic waste. Sustainability requirements. This is a general checklist of sustainability topics. More specific requirements can be based on rating systems like BREEAM or LEED.