The location for HVAC equipment should be accessible only to authorized personnel, but should also allow for proper ventilation. Mechanical equipment storage should have flush mounted vents located out of reach. Spacing of vent slats should not allow persons to reach in or to pass objects through them, potentially causing damage to equipment or exhaust fans.
Exterior condensing unit enclosures should be designed using materials that are difficult to climb and that provide (side) protection from thrown projectiles. Access doors should be solid with concealed hinges and locked with dead bolt hardware.
Locating these structures in areas where general site lighting is used will make nighttime surveillance easier without having to install direct lighting.