When it gets blazing hot outside, besides going for a swim or taking in a movie, there are only a few ways to stay cool.

Among possible solutions for keeping the house comfortable on those hot summer evenings:

—Natural air circulation.

—A fan.

—A swamp cooler (water cooler).

—An air conditioner (refrigeration cooler).

Each alternative has its advantages as well as some disadvantages.

The main advantage of natural circulation is that it is by far the least expensive way to stay cool. Mother Nature does all the work: Opening windows and doors at the cool side of the house and at the hot side of the house can create a natural air current through the home.

If there is enough temperature difference between the warm and cool sides of the home, quite an in-home breeze can result. Unfortunately, natural air circulation isn't always the most effective cooling method -- Mother Nature can often be unreliable.

Adding a simple table or floor fan to the natural circulation equation can improve air flow by giving Mother Nature a nudge in the right direction. And with several large fans you don't need to worry about Mother Nature at all -- but be prepared for dry sinuses when sitting in the path of a fan. Oh, and you may want to have wetting drops handy for dry eyes, too.

A swamp cooler (or water cooler) uses a fan to draw outside air through a water-soaked nylon-mesh. The drawn air also becomes water-soaked and is then blown into the home. As the moisture in the air evaporates it cools (a natural fact of physics), resulting in a cooler house.

A swamp cooler works really well, is inexpensive to purchase and install, and the operating expense is minimal compared to refrigeration units (air conditioners).

But swamp coolers do have drawbacks. They can substantially raise the humidity in the home, which is not a bad thing in dry-to-arid climates. However, in other surroundings a swamp cooler can promote the growth of mold and mildew, not to mention unusual amounts of rust.

Swamp coolers aren't very efficient air-filtration devices, either. The average swamp cooler probably adds to the degree of home pollution because its principle of operation is based on bringing poorly filtered outside air into the home.

Refrigeration units work by blowing outside air over refrigerated coils, sending the cooled air into the home. Essentially, with this type of unit your home becomes nothing more than a gigantic refrigerator. Only cooled air is forced into the home - no water. Because of the absence of water the air is dry and it can be easily and more effectively filtered.

Refrigeration cooling is the most people-friendly kind of cooling precisely because the cooled air is dry. Refrigeration cooling actually removes humidity, thus reducing the chances for mold and mildew, in most places. And keep in mind that when air filtration is effective, most allergy-causing particles are eliminated.

The bad side: Refrigeration coolers are the most expensive to purchase, install and operate.

By the way, even if you have central air conditioning, it may be wise to look into a small refrigeration unit that will cool a single, frequently used room. For example: If you spend 80 percent of your time in the family room, why bother cooling the entire home?