Underground enclosed parking garages provide several environmental benefits over surface lots. Major benefits include more efficient land use, no stormwater runoff, no contribution to the heat island effect, and more effective containment of pollutants.
An underground enclosed parking garage does require mechanical ventilation and more lighting than a surface lot. But careful design and control of these two systems can nearly eliminate the already minimal energy footprint of the underground garage.
Lights in a parking garage are typically on at all times, yet occupants are only in the space for short intervals of time. An efficient lighting solution is LED lights with bi-level occupancy sensors. In contrast to typical occupancy sensors, bi-level occupancy sensors reduce light output to a lower level when the parking garage is vacant, rather than turning them off completely. This makes occupants feel safer because they are never walking into a dark parking garage.
Heating and ventilation
Solutions for controlling the amount of energy needed to ventilate and heat an underground parking garage begin with demand-control ventilation, which most building energy codes require. Minimizing unnecessary ventilation in underground parking garages also reduces heating load. Heating energy can be minimized ever further by using a high efficiency heater and pre-heating the outdoor air using a lower temperature heat source.