According to an aspect of the disclosure, a controller is disposed at a site and includes a communication device capable of establishing a WIFI network to communicate with a mobile device. The controller is further configured to detect the mobile device establishing or losing a WIFI connection with a WIFI network, alter an operating condition at the site in response to detecting the mobile device establishing the WIFI connection and alter an operating condition at the site in response to detecting the mobile device losing the WIFI connection. A method of proximity control using a WIFI connection includes detecting a mobile device establishing or losing a WIFI connection with a WIFI network, altering an operating condition of a site in response to detecting the mobile device establishing the WIFI connection and altering an operating condition of the site in response to detecting the mobile device losing the WIFI connection.