The softside waterbed, also known as hybrid waterbeds, combine the comfort and superior ergonomics of fluid support systems with the look, surface feel, and ease of use of an innerspring mattress. This is usually achieved by replacing rigid wooden frame waterbed sides (hardside), with soft foam. Every manufacturer sets out to achieve this a little differently, with some more successful in design than others. While some have come and gone, there are still several successful softside waterbed manufacturers that can still provide you with several choices of differing models to choose from. For this post, we will narrow these down to three basic types; Deepfill, (requires a waterbed heater), Midfill, (heater optional), and Shallowfill, ( heater not required or recommended).
Deepfill waterbeds have eight inches of water, and are most similar to their hardside counterparts, requiring that a heater be used because the user is in close contact to the watermattress, which has about 200 gallons of water in a king size. A standard waterbed heater (300 watt) can be used on this type of waterbed, but only if it is placed on a wooden surface. If the deck surface is made of foam or fabric, a low-watt heater (120 watt) should be used instead to reduce the risk of overheating the heater, and scorching the foam or fabric surface, which can lead to heater failure or, in extreme cases, fire damage.
These lower wattage heaters operate at a lower temperature using a wire alloy heating element, which is a bit more expensive, instead of stainless steel or foil.
Midfill waterbeds have about six inches of water, and augment that with at least two inches of foam over and/or under the watermattress. A low-watt heater ONLY can be used for this type. Full watt waterbed heaters should never be used on a midfill waterbed, as they produce more heat than can be carried off and dispersed by the watermattress, creating an overheating hazard.
Shallowfill waterbeds do not need a heater, as the ambient air temperature, combined with body heat is adequate warmth. Shallowfill can be either a tube system, or a watermattress. While some may think it's safe to use a low-watt heater, aka a tube heater, we do not recommend doing so.
There is also the issue of electromagnetic frequency (E.M.F.) with regard to waterbed heaters to be discussed. This will be the subject of a later post.