Why use a whirlpool or air tub at all? Other than the fact that it feels good, it just may be good for you, too. You can get fancy, if you want, by calling it hydrotherapy. Hot water relaxes your muscles and jets massage and soothe your body. Proponents of hydrotherapy believe that it eases joint pain, improves circulation and is beneficial to the body's overall healing process [source: American Cancer Society]. In fact, it was hydrotherapy that launched the hot tub business. After engineering a submersible pump that could be used in a bathtub for a family member's hydrotherapy needs, the Jacuzzis built the first integrated whirlpool tub in the 1960s [source: Jacuzzi].
Whirlpool tubs mix air and water and force the mixture through outlets toward the person sitting in the tub. Manufacturers build outlets for the jets into the seating areas of the tub to massage and soothe tired bodies.
Air tubs create a much gentler massage by compressing air and jetting it out through the bottom of the tub via many smaller outlets. Millions of small bubbles rise through the water and surround the body, creating a less intense, effervescent massaging sensation. Tubs that combine air and water jets are also available and allow users to vary their massage depending on preferred pressure.
Air tubs are slightly easier to maintain and keep clean than whirlpool tubs. The fact that air tubs jet air means that they rarely allow excess water to build up internally, preventing mold and mildew from growing in and around the piping and pump. Whirlpool tubs that use water in their jets should be cleaned periodically according to the manufacturer's directions, usually with a disinfectant and possibly bleach [source: Heloise]. You can also buy purpose-made whirlpool cleaning solutions.
Air tubs are a little more expensive than water-jetted tubs at an entry-level price point. You can find water-jetted tubs starting around $500 and air tubs at about $1,200. Higher-end tubs of both types can be found between $3,000 and $4,000. Combo tubs are the most expensive with prices running from about $1,000 to over $5,000 [source: Consumer Reports].