Office HVAC system uses frost prevention fans and natural ventilation.

Kakegawa City Hall, completed in March 1996, contains a sixstorey high glass-walled atrium integrated into the open-plan main office areas via stepped terraces. To save energy while still providing a comfortable indoor environment, the type of HVAC system adopted required careful consideration. Frost prevention fans normally used for tea plantations were installed on the terraces to blow warm air downwards during the heating season. Transferring air from the ventilation windows in the office spaces to those in the upper parts of the atrium also achieved effective natural ventilation.