Evaluation of energy-saving methods Chrysler Building Location: New York, New York Building Type: commercial office tower Construction System: steel frame, metal cladding This report describes energy-saving measures taken by the building manager of the Chrysler Building. These measures range from the simple and quick to the expensive and time consuming. The most significant energy saving measures were achieved by planting a variety of plants with different growth characteristics, both on the roof and on individual office balconies, which added cooling shade in the summer. The use of inexpensive exterior bamboo blinds during summer months produced significant reductions in need for air-conditioning, which saved the Chrysler building a considerable amount of money. Surprisingly, installing double-paned windows was the least cost-effective measure, despite recommendations by environmental organizations. Future contributions to the Chrysler Building energy-saving initiative will include planting deciduous trees. In the summer, these will provide shade in the winter, the leafless branches will allow sunlight into the building's interior. Note: Building design accounted for 30% of energy emissions and the construction materials of the Chrysler Building accounted for another 30%. What is the main topic of the report?