If you are installing an air conditioner for the first time, then making sure that all of this ductwork is in place can get costly. Generally, ductwork can tack on additional $2,000 to $3,000, and that will vary depending on the home.However, if you are simply replacing your air conditioning unit, then there may be little to no added cost for this component.Adding other updates, like a new thermostat, may also increase the total price.he national average cost is between $4,500 and $6,200, but it could be much higher (or lower) depending on your individual situation. Here are a few factors that will affect the overall cost of your installation project: