The buildings have a central heating and air conditioning system which can be individually controlled in your unit. This is the most efficient approach and uses the least amount of energy overall. For air conditioning, a chiller unit on the roof generates cold water which is circulated through the building to individual fan coil units in each suite. There the cold water is converted to cold air which is then forced out through ducts. Likewise, for heating, the central boiler sends hot water through the building which your fan coil converts to hot air which is then blown through your suite. If you live in the phase 1 or 2 buildings, your fan coil contains a supplemental electric heater to provide heat during cold nights after the building has been switched over to cold water circulation (i.e. air conditioning) in the spring, or before it has been switched back to hot water (i.e. heat) in the fall. If you live in the phase 3 building, the central boilers provide hot water for heating during the fall, winter, and spring seasons. Cold water is also provided for air conditioning when the chiller is operating during the warm months. Where necessary, your suite also contains electric baseboard heaters as a supplemental heating source in very cold temperatures.