Waterbeds primarily consist of two types, hard-sided beds and soft-sided beds.

A hard-sided waterbed consists of a water-containing mattress inside a rectangular frame of wood resting on a plywood deck that sits on a platform. Platforms may incorporate drawer systems for storage. Frames may be decorative, with elaborate headboards or tall posts.

A soft-sided waterbed consists of a water-containing mattress inside of a rectangular frame of sturdy foam, zippered inside of a fabric casing, which sits on a platform. The effect is to look like a conventional bed and is designed to fit into existing bedroom furniture. The platform usually looks like a conventional foundation or box spring, and sits atop a much-stronger-than-normal metal frame.

Early waterbed mattresses and many inexpensive modern mattresses have only one water chamber. These mattresses are commonly described in the industry as "free flow" mattresses. When the water mass was disturbed, significant wave action could be felt. They needed some time to stabilize after a disturbance. Later types employed wave-reducing methods, including fiber batting and interconnected water chambers. More expensive "waveless" modern waterbeds have a mixture of air and water chambers, usually interconnected.

Softside Waterbed 160 × 200 cm with two waterchambers and flexible chamberisolation insideWater beds are normally heated. Temperature is controlled via a thermostat and set to personal preference, but is most commonly average skin temperature, 30 Degrees C or about 96 Degrees F. A typical heating pad consumes 150–400 watts of power. Depending on insulation, bedding, temperature, use and other things, electricity usage may vary significantly.

Waterbeds are usually constructed from vinyl or similar material. They can be repaired with nearly any vinyl repair kit.

http://en.wikipedia.org/wiki/Waterbed

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