An air conditioning system comprising: at least one air conditioner; a client terminal to centrally control the at least one air conditioner and provided with a display device; and an air-conditioning control and monitoring apparatus which is connected to the at least one air conditioner via an air-conditioning control network and which is connected to the client terminal,, via a communication network to supply operating status information of the at least one air conditioner to the client terminal, wherein the air-conditioning control and monitoring apparatus includes: an air-conditioning monitoring-information storage unit configured to store the operating status of each air conditioner; a monitoring-screen creating unit configured to create monitoring screen data on the basis of the operating status stored in the air-conditioning monitoring-information storage unit; a communication unit configured to send the monitoring screen data created by the monitoring-screen creating unit to the client terminal, characterized in that the air-conditioning control and monitoring apparatus further includes: a link setting unit configured to set a URL that is assigned to the air conditioning control and monitoring apparatus as link information related to monitoring screen data to be displayed next on the display device of the client terminal and configured to set a waiting time determining a time for which the monitoring screen data created by the monitoring screen creating unit is displayed on the display device of the client terminal; whereby the communication unit is further configured to send the link information and the waiting time set by the link setting unit to the client terminal. at least one air conditioner; a client terminal to centrally control the at least one air conditioner and provided with a display device; and an air-conditioning control and monitoring apparatus which is connected to the at least one air conditioner via an air-conditioning control network and which is connected to the client terminal,, via a communication network to supply operating status information of the at least one air conditioner to the client terminal, wherein the air-conditioning control and monitoring apparatus includes: an air-conditioning monitoring-information storage unit configured to store the operating status of each air conditioner; a monitoring-screen creating unit configured to create monitoring screen data on the basis of the operating status stored in the air-conditioning monitoring-information storage unit; a communication unit configured to send the monitoring screen data created by the monitoring-screen creating unit to the client terminal, an air-conditioning monitoring-information storage unit configured to store the operating status of each air conditioner; a monitoring-screen creating unit configured to create monitoring screen data on the basis of the operating status stored in the air-conditioning monitoring-information storage unit; a communication unit configured to send the monitoring screen data created by the monitoring-screen creating unit to the client terminal, characterized in that the air-conditioning control and monitoring apparatus further includes: a link setting unit configured to set a URL that is assigned to the air conditioning control and monitoring apparatus as link information related to monitoring screen data to be displayed next on the display device of the client terminal and configured to set a waiting time determining a time for which the monitoring screen data created by the monitoring screen creating unit is displayed on the display device of the client terminal; whereby the communication unit is further configured to send the link information and the waiting time set by the link setting unit to the client terminal. a link setting unit configured to set a URL that is assigned to the air conditioning control and monitoring apparatus as link information related to monitoring screen data to be displayed next on the display device of the client terminal and configured to set a waiting time determining a time for which the monitoring screen data created by the monitoring screen creating unit is displayed on the display device of the client terminal; whereby the communication unit is further configured to send the link information and the waiting time set by the link setting unit to the client terminal.