One important thing is the stability because the weight and water pressure is great when filled with water and in use. The thickness of the material and how stiff the structure itself is then plays a major role. The wall and bottom thickness of SpaDealers hot tubs from polyethylene plastic is 6-8 mm. It makes a big difference to the stability of the final product, compared to brands where the thickness is 4 mm. Since material costs are a large part of the production costs, a lighter product is cheaper to build, which is the reason most brands try to save on material.
To further increase stability, we use a stable support frame where the hot tub is "anchored". These factors contribute to making SpaDealers hot tubs probably the most stable plastic hot tubs on the market today. An easy way to check a product's stability is to grab the edge with both hands and pushing back and forth. A product with thin material will bend and sway.
There are also different ways to insulate. Both in terms of construction or insulation material. To achieve an effective "total insulation" this requires that the bottom and sides are insulated with a material of sufficiently good R-value. It is not enough merely to have insulation under the seats. This is usually only added in other brands so the seats won't sag frm the load during use. Moreover an insulated cover is needed. And one should not forget to protect the equipment on the outside, such as heaters and filtration equipment. SpaDealers are experts at this
The picture here shows how we construct our plastic hot tubs. No compromises are allowed in building the market's most robust hot tub.