I guess soemeone told you that AC is positive pressure. Actually, when installed correctly, there is no pressure difference from room-to room or from inside to outside. Thus it is made difficult to understand why you are enthused about the idea. All that will happen is that air must come into the house from the cracks around windows and doors to replace that which goes out through the exhaust fan.

http://www.heatpro.us FREE heat/cool right-sizing

Yes, you really have to find out the MAKE and MODEL to get good answers. There IS more than one machine made.