Controller, energy management system, remote control method, and program

In an energy management system (1), a controller (100) acquires an environmental parameter which represents an indoor environment. The controller (100) accepts a remote control request from an outdoor terminal device (40A) with respect to an air conditioner system (104) or other device installed indoors. Upon accepting the request, the controller (100) transmits query data, which includes the acquired environmental parameter and a query as to whether to control the device as per the request, to the terminal device (40A). On the basis of a response to the query from the terminal device (40A), the controller (100) controls the device.