Acrylic vs. Fiberglass Hot Tub Shells: Key Differences and Features

Our journey as manufacturers began in 2017 with fiberglass hot tubs. A few years later, as trends and customer needs evolved, we expanded our range to include acrylic models, before discontinuing fiberglass hot tubs entirely in 2025. Having worked with both materials, we would like to share their characteristics and help answer a question many customers face: which should you choose?

A brief introduction to each material:

Fiberglass is a composite material made from fine glass fibers combined with various resins. This combination creates a strong, lightweight, and water-resistant material that is well suited to manufacturing hot tub shells. Research suggests that a fiberglass shell can last between 5 and 20 years, or even longer. However, its lifespan may be shorter if you purchase a low-cost hot tub made from inferior materials or fail to maintain and clean the shell after each use.

Even when manufactured by skilled professionals using high-quality materials, fiberglass shells are prone to fading, scratch easily, and can lose their original appearance relatively quickly. The choice of colors is also limited. However, fiberglass is a considerably cheaper option, making it suitable for those looking for a budget-friendly solution.

Fiberglass hot tub shells first appeared around the 1970s, but acrylic shells soon began to replace them. This shift made it easier to keep hot tubs clean, as acrylic surfaces required less maintenance.

Acrylic hot tub shells are made from a single sheet of acrylic, which is heated until pliable and placed over a mold. A vacuum then draws out the air between the sheet and the mold, shaping the acrylic into a smooth, evenly formed shell. This process requires specialized equipment. To give the finished acrylic shell additional strength, its underside is reinforced with fiberglass.

Acrylic is a much stronger material, offering greater resistance to impacts and scratches, with any scratches that do occur being less noticeable. It is durable and has a smooth surface that feels pleasant against the skin.

The quality of the acrylic also plays an important role in how well your hot tub retains its condition over time. At Sidabras Spa, we use certified, premium-quality acrylic made in the USA. Acrylic is considered one of the best materials for hot tub shells, which is why leading hot tub and spa brands worldwide—including Bullfrog Spas, Jacuzzi, ThermoSpas, Sundance Spas, Hot Spring, and Caldera Spas—use it.

High-quality acrylic is durable, energy-efficient, and visually appealing. When combined with high-quality insulation, it also helps retain heat effectively. Another key advantage is that acrylic is much easier to maintain and clean, although it is more expensive than fiberglass.

Before purchasing a hot tub, our team reccomends visiting a manufacturer’s showroom  to see both types in person. This can make it much easier to decide whether an acrylic hot tub is worth the additional investment or whether a fiberglass model will meet your needs.