54. The amazing earth tube cools office tower

Earth tubes are a simple, passive geothermal system that takes advantage of the earth’s constant temperature below the frost line. By drawing fresh air for your building through an earth tube you pre-heat or pre-cool your air depending on your needs. This saves you a ton of money, according to architect Tang Lee an earth tube system can save you up to half of your ventilation heating costs. At the Epcor Tower it saves the building $50,000 a year.