While the difference isn’t always immediately noticeable, the material used in your hot tub shell can greatly impact the durability, appearance and comfort of your spa.
Here we’ll explore the most common materials used in hot tub shells and the pros and cons of each.
Acrylic shells are made by melting a sheet of acrylic over the mold of the tub. Vacuums pull air out from between the acrylic and the mold, leaving an even, smooth surface.
Acrylic is considered one of the most durable materials for a hot tub shell. However, it is heavier than some of the other options, making it easier to move and install. Acrylic can also cost more than materials like vinyl and fiberglass.
Make certain to ask if an acrylic shell is backed or unbacked, as this will affect the strength of the shell. Backed acrylic has a layer of the polymer ABS bonded to its underside, and the two are melted together into the mold. Unbacked shells may have a layer of fiberglass underneath.
Backed acrylic can be melted into deeper tubs than unbacked acrylic can, and the resulting surface is non-porous and highly chemical-resistant. The extra layer of material may also make for better heat retention.
One other thing to consider with acrylic is surface texture. This material is available with smooth, glossy surfaces or with a slightly rougher feel. Both are of high quality – choosing is a matter of preference.
Vinyl is typically used in soft-sided (such as inflatable) hot tubs or stretched over another material as a liner. It’s most commonly seen in low-cost and portable hot tubs.
While you will certainly pay less for a vinyl shell and be able to move it easily, you probably won’t get as much use from this kind of spa. Vinyl is not very durable and thus prone to cracks and tears far sooner than other materials. In some cases, damaged vinyl can be repaired.
In addition to low durability, vinyl hot tubs are more likely to fade and discolor from water chemical imbalance or sun exposure. These tubs are also highly inefficient when it comes to heat retention.
A wide range of plastics can be used to make hot tubs, and one method is rotomolding plastic. This uses a plastic powder that is placed on a mold, heated until it melts and rotated until the entire mold is smoothly and evenly covered.
The result is a matte finish that could be considered a few steps up from vinyl. It will also be lighter and more affordable than acrylic.
While rotomolded plastic is more durable than vinyl, it’s not very heat efficient, and may end up costing more in terms of energy bills.
In earlier decades, wood was a common material for hot tub shells. Although plastic remains popular, high-end wooden tubs are still made from cedar, redwood and other trees. Purchasing a wooden hot tub is likely to cost more than buying one with a synthetic shell.
While wood generally has a more natural, classic appearance than synthetics like acrylic, it can’t be molded into smooth shapes for benches. Further, it probably won’t hold heat as well and will have higher energy costs.
Additionally, wooden hot tub maintenance is slightly more more complicated than synthetic shell maintenance with staining and sealing. At the same time, if it uses less plumbing and heating material, there’s far less to maintain in that department.
Beyond the Shell
Keep in mind that the good things about a high-quality hot tub shell will be countered by poor insulation . Be sure to learn about what’s under the shell, regardless of the material you select. Contact your Aqua Living dealer with any questions!