For television series episodes entitled "Hot Tub", see Hot Tub (Drawn Together episode) or The Hot Tub (Seinfeld episode).
A hot tub is a manmade large tub or small pool full of heated water and used for soaking, relaxation, massage, or hydrotherapy. In most cases, they have jets for massage purposes. Hot tubs are usually located outdoors, and are often sheltered for protection from the elements, as well as for privacy.
There are two different styles of hot tubs:
Hot tubs are usually heated using an electric or natural gas heater, though there are also wood-fired hot tub heaters. Hot tubs are also found at natural hot springs; in this case, the water may be dangerously hot and must be combined with cool water for a safe soaking temperature.
Water sanitization is very important in hot tubs, as many organisms thrive in a warm, wet environment. In addition to the use of a pump and micrometre-range particulate filter, bromine or chlorine are used as a primary sanitizer, and often supplemented with an ozone generator and/or UV sterilization. If ozone and UV are not used, a primary algaecide such as polyquat may be additionally needed, since these microbes are more resistant to chlorine than are most bacteria *.
Each integral seat is often equipped with one or more water jets that allows water to be directed at 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, providing a massage-like effect.
Although Jacuzzi is probably the best known brand name of spas, the company primarily concentrates on making bathroom fixtures. Other 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 at least two water pumps, with one small circulator pump serving the heating and filtration water loop and the other(s) 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 DVD players.
The spa shell is the exteriour of the tub, and is composed of a surface and an understructure that are bonded together during the manufacturing process. The surface is the source of the color, look and feel of the spa, so it should resist deterioration due to the sun, spa chemicals, or normal wear and tear. Some high-end shells have special coatings to make them more stain resistant or have anti-bacterial ingredients molded into the shell material.
The understructure of the shell is made of fiberglass, and provides the strength needed to support hundreds of gallons of water.
The spa cabinet is the skirting around the hot tub. For many years, spa cabinetry was made of wood, most commonly redwood or cedar, and this is still a popular choice today. Wood cabinets require regular maintenance, though, especially in climates where they are exposed to wind, rain, snow, or the drying effects of hot sunlight. Synthetic materials are becoming very popular because they require little or no maintenance to keep their appearance.
Hot Tub – name originally given to the earliest tubs that were round, made of wood, and located outdoors; now is commonly used interchangeably with the phrase ‘home spa’.
Home Spa – generally made with an acrylic shell; surrounding cabinet may be made of wood or synthetic materials; can be used to describe an above ground, in-ground, indoor or outdoor spa.
Portable Hot Tub/Portable Home Spa – name for any hot tub/home spa that is pre-assembled and sits above ground; actual size and features of a portable hot tub vary widely, from small portable hot tubs that weigh only a few hundred pounds and are quick to set up to large tubs that weigh several thousand pounds and require specific installation methods and electrical wiring.
Jacuzzi Hot Tub – Jacuzzi is a well-known manufacturer of home spa systems; "Jacuzzi" is often used as a generic reference to any home spa or hot tub