Municipal District Heating Services and Combined Heat and Power (CHP) systems can produce waste heat in the form of steam condensate and hot water. The authors have developed a system to use this thermal pollution to heat the soil and growth medium of green roofs and outdoor gardens. The system enables plant life to survive colder climates and increases growth often in excess of 20% (Power2013-98172). In New York City test heated green roofs, the system can save vast amounts of normally required cooling water that is tapped from the overburdened municipal supply (IMECE2013-65200).
Existing small scale green roofs in New York City and larger scale heated green roof retrofit in New York City is presented to indicate additional construction details, thermal considerations, and potential code compliance considerations.