Hot tub: Encyclopedia - Hot tub

Hot tub

A hot tub is a large tub or small pool full of heated water and used for soaking, relaxation, hydrotherapy, reading, or meditation. Hot tubs are frequently located out-of-doors although they may be sheltered against sun, rain, wind, or snow.

There are essentially three different styles of hot tubs:

• Simple wooden-staved soaking tubs
• Fiberglass-reinforced plastic spas (whirlpool tubs)
• Bathtub-sized indoor units

Hot tub - Soaking tubs

This style of tub is constructed much like a very large barrel with wooden staves. The water within is usually still, circulated only for the purposes of heating and filtering it. The tub is often inset within a wooden deck and is entered from that deck. Seating within the tub usually takes the form of wooden benches or a seat that forms a ring around the inner circumference of the tub.

The tub is filled once at system startup and is then maintained in much the same manner as a swimming pool. In simple designs, chlorine is used as a disinfectant. More sophisticated designs use an ozone generator, reducing the amount of chemicals needed to disinfect the water. The tub is heated by electricity or, occasionally, natural gas or propane, or rarely, wood fires.

Hot tub - Spas

This style of tub is very different from the wooden soaking tub. These are usually less deep and manufactured from fiberglass-reinforced plastic formed into shapes that provide a variety of seating arrangements within the tub. Each seat is usually equipped with hydrotherapy jets that allow a forceful flow of water to be directed at various parts of the body. The water flow may be aerated for additional effect and some or all of the jets may also automatically move or rotate, causing the changing pressure of the water on the body to provide a massage-like effect.

These tubs may be free-standing or recessed within a surrounding deck. If free-standing, they are usually entered by climbing a short staircase of one or two steps and then stepping over the side of the tub onto one of the seating areas. A common misconception with hot tubs is that they need external plumbing when in fact most modern units are self contained and consequently only need filling with water.

Although Jacuzzi is probably the best known brand name of spas the company now concentrates on making bathroom fixtures and the spas sold under the Jaccuzzi brand are actually made by Sundance. Spas are manufactured by a wide range of mostly-boutique (small production) vendors.

Effective insulation greatly improves the energy efficiency of a spa. There are several different styles of spa insulation: some manufacturers fill the entire cabinet with foam, while others insulate the underside of the shell, the inside of the cabinet, or both. Not surprisingly, many manufacturers advertise the superiority of their approach to insulation, but few independent side-by-side comparisons are available.

Spas usually have several independent water circuits with one providing heating and filtration and the others driving the hydrotherapy jets. Sophisticated computer controls are now common and many tubs now are equipped with extensive lighting, sound systems, and even flat-screen televisions with integral DVD players.

Hot tub - Bathtubs

Much smaller spas are now commonly available for installation within an ordinary bathroom. Resembling conventional bathtubs, they are filled afresh for each use, don't contain any heating or filtration mechanisms, and usually contain just one hydrotherapy water circuit. They may accommodate one or sometimes two people simultaneously.

See also

• Sauna
• Finnish sauna

Adapted from the Wikipedia article "Hot tub", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki