Energy management and energy efficiency should start with all HVAC equipment, suggests Smith. However, he says, in the case of large facilities with larger HVAC systems, this is easier to do from the beginning. For that equipment and those facilities with long-term leases or ownership, the upfront costs and complexity in setup, along with the ongoing maintenance, are justifiable. Facilities with rooftop air-conditioning equipment have historically been facilities with short term leases, little sophistication in the level of facility personnel on site to manage the equipment, and  strict upfront cost pressures that force equipment choices with little technology installed or in setup. As technology has improved in the reliability and the cost of components required to modify the HVAC equipment, it has become easy to justify adding this technology to package rooftop equipment.