The time it takes to install an AC system depends on factors like the type and complexity of the system. Generally, a central air system can take one to three days to install, while a ductless mini-split system may take one to two days. When partnering with a highly experienced HVAC company like Logan Services, you can expect most system installations to finish in just one day. A window unit can be installed in just a few hours. A professional HVAC technician can provide a more accurate time frame based on your specific situation.