Waterbed Guide:
Reinventing a Cult Favorite

Waterbed Overview

Though waterbeds have declined in popularity since their peak in the 1970's, they retain a core following. Devotees generally praise waterbeds for their lack of pressure points, controllable temperature, and all-around "groovy"-ness. Critics have traditionally derided their lack of firm support, disturbance caused by your partner's movements, and fear of leaks. In recent years though, improvements to the waterbed core have served to reduce unwanted motion, add lumbar support, and greatly decrease the incidence of leakage. In addition, many of today's waterbeds have come to look much like traditional innerspring mattresses, offering layers of upholstery on top of a core that contains water rather than coils. Together, these upgrades have addressed many of the comfort, support, and durability issues encountered by previous generations of waterbeds.

Types of Waterbeds

Generally speaking, there are two types of waterbeds available on the market today — "soft-sided" and "hard-sided."

Soft-sided waterbeds, the newer and more popular type, feature a water-filled chamber (sometimes referred to as a "bladder") encased in sturdy foam and upholstery, making their external appearance closely resemble that of a traditional innerspring mattress. The bladder is held in place by stiff foam rails on each side, sometimes referred to as foam encasing, which also provide edge support for the mattress. Foam encasing rails that are somewhat thinner near the top surface of the mattress but wider at the bottom tend to maximize sleeping area while preserving durability. A soft-sided waterbed can generally sit on a traditional mattress foundation, such as a box spring, though their hefty weight necessitates the use of a heavy-duty bed frame with a center support. Soft-sided waterbeds, sometimes referred to as "hybrids," typically feature several layers of upholstery on top of the bladder as well. These can be evaluated in the same way as the upholstery in an innerspring mattress.

Hard-sided waterbeds, the classic model, feature a relatively unstructured bladder placed inside a special wood "frame," which holds the mattress in its proper shape. The frame sits on top of a "deck," a specially designed platform for waterbeds that evenly distributes the weight of the mattress, so as to minimize strain on both the bladder seams above and the floor below. Hard-sided waterbed foundations often feature a padded rail along their perimeter that helps to ease entry and exit, however getting in and out of a hard-sided waterbed can still take some getting used to. Hard-sided waterbeds typically offer much less upholstery on top of the bladder than soft-sided waterbeds (and in many cases none at all), making temperature control and motion separation important issues to consider.

Waterbed Heating and Comfort

One of the most popular aspects of waterbeds is the ability to control their temperature. Waterbed enthusiasts frequently cite the therapeutic benefits of sleeping on a heated mattress, and anyone can appreciate the appeal of a warm bed on a cold evening. Heating is provided by a specially designed pad that sits beneath the mattress. Precise temperature is a matter of personal preference that can typically be controlled by a thermostat on the heater. Experts suggest that a temperature between 81 and 86 degrees Fahrenheit (27 to 30 degrees Celsius) is best for most people. Due to their significant cushioning, heating is considered optional for soft-sided waterbeds. However, it is strongly recommended for hard-sided waterbeds, where there is less separation between your skin and the water.

Waterbed Motion Separation and Support

Conventional "free flow" waterbeds have long been known for the "waves" that travel freely across their surface upon the slightest movement. Though this sensation is often cherished by traditional waterbed fans, for many others, waves are considered a source of disturbance from peaceful sleep and a sign of insufficient spinal support. In recent years, the waterbed industry has made great strides in developing techniques to counteract these concerns, while still preserving the original benefits of a water-based core.

One way that manufacturers have addressed this point is by placing motion dampening materials, such as layers of fiber batting (a felt-like material), into the bladder. This solution, known as "fiber filling" or "baffling," is used in both soft-sided and hard-sided waterbeds. Fiber filling serves the dual purpose of reducing motion in the water as well as increasing the firmness of the bed. In general, more fiber filling results in greater motion separation and firmer support. Options range from semi-waveless (50% motion reduction) to ultra-waveless (95%+ motion reduction). Fiber can also be used to bolster support in specific areas of the mattress, such as for increased lumbar support. Many people even find that the reduced motion and increased firmness makes fiber-filled waterbeds easier to get into and out of. Conversely, fiber filling can complicate draining of the bladder due to its retention of water, and on rare occasions can cause discomfort in the event it becomes un-tethered and begins to move around within the bladder.

The second approach to achieving enhanced support and motion separation in waterbeds entails compartmentalizing the water. With a dual mattress system, also known as "dual bladders," water is divided between two separate chambers, providing motion separation and allowing for different levels of fiber filling (for support) and temperature (for comfort) on each side of the bed. With a hydraulic waterbed mattress, the bladder is divided into numerous small compartments, but the water is allowed to travel between the compartments in a controlled manner via small holes. This form of compartmentalization results in a more gradual responsiveness to movements and a firmer level of overall support. In some hydraulic mattress designs the compartments are cylindrically shaped, causing some to refer to them as "coils" even though they lack any true spring action.

Waterbed Construction and Durability

Waterbeds are carefully constructed to avoid leaks, punctures and bursting; and technological advances have significantly reduced the occurrence of such problems. Bladders are generally made of heavy duty vinyl that contains materials similar to those found in PVC piping. In addition to its superior water containment, vinyl's non-porous nature makes it less likely to harbor mold, dust mites, or other allergens. The thickness of vinyl used for waterbed bladders is usually between 20 and 30 millimeters, with thicker vinyl providing better protection against punctures. Bladders are sealed tightly using a variety of methods. Reinforced corner panel seams typically provide the most reliable seals, although radial lap seams can work fine as well. Butt seams are generally considered the weakest and least durable. Most waterbeds also feature a safety liner around the bladder, which offers additional protection in the event of a problem. It is worth noting that since new waterbeds are sold empty, both soft-sided and hard-sided waterbeds will require some assembly once you get them into your home.

Waterbed bladders feature varying levels of depth, or "fill levels," ranging from shallow (3 to 5 inches) to mid-fill (5 to 6 inches) to deep fill (7 to 8 inches). Shallow fill levels are generally only used in soft-sided waterbeds, where the bladder is surrounded by foam and typically covered with several layers of upholstery. All else being equal, the deeper the fill, the more potential there is for movement, which is largely a matter of personal preference.

Waterbed Sizes

Hard-sided waterbeds are generally not made in traditional bed sizes, but rather are available only in California King, California Queen and Super Single. Soft-sided waterbeds come in ordinary bed sizes — such as King, Queen and Full — and thus can use ordinary sheets and bedding, as well as traditional foundations.