A monitoring system for apparatus and systems in commercial and residential properties is provided. The monitoring system consists of a head unit and a tail unit, each of which has one or more sensors that measure performance parameters that are important to understanding the performance of the apparatus and system being monitored. As an example, an HVAC system may be monitored to determine when an air filter needs to be changed, or to predict when failure of the HVAC system may be imminent. The sensor array in the head unit and tail unit measure performance and report alerts and historical system performance to users through a mobile app, social media accounts, or any other system for communicating over a wired or wireless network connection.