Air conditioning systems are widely used nowadays; innovations and advancements are already available in the industry. The HVAC System became a topic during a Coronavirus Pandemic or COVID-19. Our government has carefully studied policies, procedures, and guidelines in the installation of HVAC or air conditioning systems in health service facilities and one minimum required of a healthcare facility with proper ventilation is window-type air conditioning. Furthermore, maintenance of equipment and proper equipment care has become a concern, especially in operational costs. This research will perform an assessment and evaluation for window-type air conditioning to determine the reliability, risk, and operational cost of performing preventive maintenance or a conditioned-based (predictive) maintenance through the use of a mathematical approach with integration of the linear programming concept. It was revealed that the preventive maintenance program was more cost-efficient than the conditioned-based or predictive maintenance having a difference of PHP 126,500.00.