The windows in my house are just not suitable for a window air conditioner. Several years ago, I bought a roll-around air conditioner shown in the picture below.
If you have one of these, you know that it vents the hot air out through a duct that goes from the back of the unit to a nearby window. One problem with this arrangement is that the duct gets fairly hot. I have always felt that the air conditioner can barely keep up with the heat it is generating itself and putting into the room because of the hot duct.
After about 5 years of ownership of this unit, I finally had a bright idea. Today is the first day it has been hot enough outside to see if my idea works. It does.