Central air conditioning is the most comprehensive way to cool a home. That being said, it isn't necessary on every property. A central AC system could prove to be superfluous in a region that has mild summer temperatures. Also, in smaller buildings, central AC could be wasteful. You just don't need that much power and machinery to cool down such a small space. Basically, there are few alternatives they can be used to keep your home cooler during the summer.
1. Window AC Units
Window units are the first thing that comes to mind. Many people run to the home improvement store and buy window units as soon as the first truly hot summer day hits. In fact, during a heat wave, your local stores could very well sell out of their window AC units in a matter of days. They are extremely popular because you can run into the store, buy one, and have it pumping cold air into your home within just a couple of hours. You don't need to have an HVAC professional do the installation.
2. Portable Units
Window units are the most effective because they are able to draw outside air to help in the creation of cold air. There are also portable units that can be placed anywhere in the house. These units don't work quite as well because they have to recirculate interior air. This means they use more electricity trying to recirculate air, which can be very wasteful. Regardless, both of these systems will use a lot more electricity than a traditional fan or air mover. The main difference is they have a compressor and evaporator which help to create cold air and remove moisture from it.
3. Swamp Coolers
Swamp coolers are similar to AC units in that they have to be mounted on a window. You often see swamp coolers on roofs of flat buildings. Swamp coolers use liquid, along with electricity to create cold air. They turn hot, dry air into cold, moist air, which can be problematic for some. Since they actually add moisture to the air, swamp coolers can make your interior feel a little muggy.
All three of these options will make your interior cooler. They are more effective than portable or ceiling fans. Each of these alternatives will use much more electricity than a normal fan. That said, they will also all be cheaper than installing a central AC system. For more information, contact your local HVAC services.