The answer to 'how much to replace AC' is that the cost to replace a central air conditioning system can vary widely, but typically ranges from $3,000 to $10,000 or more. The exact price will depend on factors like the size of your home, the efficiency rating of the new unit, whether any ductwork needs to be replaced, and the complexity of the installation.
It's important to get quotes from multiple local HVAC contractors, as pricing can vary significantly by location and contractor. They will be able to assess your specific needs and provide a customized estimate. Be wary of any contractor that gives you a price without first inspecting your home and system.