Wright’s plans for heating Unity Temple included a forced air system, which was an original design with an ingenious concept for its day. However, the system never functioned properly, especially for Midwest winters.
Within a year after the building was completed in 1908, the Congregation installed a radiant heating system, which has been the building’s main source of heat for the past century. Cooling the building has depended solely on natural ventilation. Unity Temple’s electrical and plumbing systems have never been fully upgraded and the building does not have life safety systems.
During the restoration, all building systems were completely revamped to comply with current building codes, and a geothermal system will be installed to heat and cool the building. After conducting a thorough study of moisture that collects in the walls of Unity Temple and throughout the building, it was determined that the original system utilizing perimeter radiant heat would be retained and supplemented with forced air heating in winter and cooling in summer.
Unity Temple has never had an air conditioning system for the warm summer months, and the lack of climate control has caused damage to the concrete structure and interior finishes, as well as discomfort for the Congregation and visitors. Additionally, rising energy costs made it a very expensive to heat the building.
Unity Temple Restoration Foundation and the Congregation maintain a strong commitment to making Unity Temple as sustainable as possible, in a way that does not compromise, structurally or visually, the architectural significance of the building.
The restoration now equips the building with a state-of-the-art geothermal ground source heat pump: an electrically powered system that taps stored energy from the earth, using the earth’s relatively constant temperature to provide heating, cooling, and hot water. For the first time, Unity Temple is cooled during warm summer months.
Currently the most energy efficient, cost-effective heating and cooling system available, the geothermal system will reduce reliance on fossil fuels to create a comfortable year-round environment. The system is simple to operate and maintain, requiring no exterior equipment or noise, and will aid in preventing future structural and surface deterioration, protecting the exterior concrete structure and interior finishes of Unity Temple.