Air conditioners have come a long way from the days of fans and window units. Early air conditioners were noisy, inefficient and costly to operate. Today's central air units have made great strides in all three areas.

The cost to install a central air conditioner will vary greatly depending on the size of your home and the amount of work that needs to be done. If the air conditioner can be attached to duct work, the cost will be much less than if new duct work has to be added, particularly if the ducts have to be run through walls (thus requiring drywall repair and replacement). There are ductless systems available, but these systems are not widely used in the United States, where most homes have duct work, or at least the space for it. The duct-free systems tend to be more expensive, but it may be worth comparing prices if you add to have ducts anyway.