I are now living in Houston Texas and summer temps are usually in the 90's for a year of the year. My home is relatively new and has an excellent quality central HVAC system. In spite of much of my air conditioner is accomplished by the earlier technology of a room or perhaps "portable ac unit - go!! -" window unit.
My bedroom unit is a 12,500 BTU Energy Star design that cost about $260. It is not rated being as effective as my central product but consumes less energy per BTU in my opinion. This's since it doesn't run a huge fan to blow air through the overall house. We run the window product from aproximatelly 8PM to 8PM on warm days. When we're not home the central device is shut down and the window product keeps the house aproximatelly 15 degrees cooler than the exterior for our 1,900 sq foot home. It also keeps the moisture low. We supplement the window product when we are home with the central AC. Cooling the home this way reduces our energy costs. We finally run the central unit about 50 % less, therefore it needs to have a prolonged life. On the very hot days, when running the window product and also the central unit, we get additional cooling power.
In Texas it is a huge deal when your central AC fails throughout the summer. We run a second 12,000 BTU unit once the central AC is broken. Which makes the house livable during the remedy time.
Another benefit of having window AC units happens when there's a power failure. Windstorms as well as hurricanes are routine in the Houston area. We like having a generator along with window AC products as insurance for power failures. Throughout IKE we ran 2 window devices by generator for a week, together with the fridge, microwave, as well as a few lighting.