Someone once told me that window air conditioning units are better and more energy saving if you have an old home.
Running a central air conditioning system in an old home can end up costing you more to use the thing, and also, it is possible that the home may not even have ductwork, so that alone would cost a fortune! I never had actually thought about this, because I have been using central air conditioning for decades now. Because I live in the south, having window air conditioning systems are not really an option. Everyone has central heating and air conditioning. If you were to try to have a window air conditioning system in the south, you have a lot of potential issues to deal with. Not to mention, there are no windows in the way these homes are built that would accept a window air conditioning system! However, if you have an older home and live in the south, you can get yourself a portable air conditioning unit, or maybe even a swamp cooler mixed with a portable air conditioning unit. However, back to the point on hand, I did find out that having a window air conditioning unit does save tons on energy use in an older home, instead of a central air conditioning system. So, if you have an old home, go with the window air conditioning unit if you do not live in the south part of the united states of america! That is what I did for my older home that I have as a Summer getaway in the north.