Stainless Steel vs Acrylic Hot Tubs: Lifespan, Hygiene & Cost Comparison

09 March 2026

Stainless steel hot tub with solid wood surround

Choosing a luxury hot tub isn’t just about the jets or the lighting. The material it’s made from has a big impact on how it performs, how long it lasts, and how easy it is to keep clean.

Acrylic hot tubs are everywhere and can look fantastic. At SpaFlo, though, we build our spas from commercial‑grade stainless steel because it offers something different: durability, low maintenance, and a finish that still looks good years down the line.

If you’re weighing up the options, here’s a breakdown comparing the two:

Why SpaFlo Uses Stainless Steel

Stainless steel is used in lots of environments where water is constantly present. That’s one of the reasons we chose it when designing SpaFlo hot tubs in the first place. It’s naturally resistant to rust and corrosion, which makes it ideal for hot tubs and spas.

Yes, stainless steel usually costs more upfront. But in our experience, it tends to pay for itself through its long lifespan, low maintenance needs, and the fact that it continues to look and feel like a luxury product.

Stainless Steel vs Acrylic: The Key Differences

A genuinely luxurious look

Stainless steel has a premium, modern appearance that works well in most garden, home or spa settings. The reflective surface makes the water look incredible, especially in a high‑end garden or indoor spa setting.

More hygienic by design

Stainless steel is naturally non-porous and extremely smooth. This makes it harder for bacteria to form biofilms on the surface compared with softer materials that scratch more easily.

For this reason, stainless steel is widely used in hospitals, food preparation environments and commercial swimming pools where hygiene standards are critical.

Acrylic, on the other hand, can scratch or wear down over time, creating tiny areas where bacteria can settle.

In warm water environments like hot tubs, surfaces that stay smooth tend to stay cleaner.

Built to last

Longevity is one of the main reasons people choose stainless steel. A well‑made stainless steel hot tub can last 50 years or more with proper care. Acrylic tubs typically last around 10–15 years and can start to show their age a lot sooner.

Acrylic hot tubs typically have a laminated shell made from acrylic and fibreglass. Over time, these layers can separate (delamination), particularly after repeated heating and cooling cycles.

Stainless steel tubs, by contrast, are fabricated from a single structural material. High-grade marine stainless steels such as AISI 316L are designed for long-term exposure to water and chemicals and are widely used in swimming pools, marine environments and commercial kitchens.

Easy to clean

Keeping stainless steel clean is simple. Most of the time, a microfibre cloth and mild cleaning products are all you need, no harsh chemicals required. Learn more about how to clean a stainless steel hot tub.

Ready for winter

Outdoor spas in the UK need to handle cold weather without fuss. SpaFlo stainless steel spas are designed to handle UK winters, so you don’t need special treatments or to worry about frost damage.

No UV fading

Acrylic is a polymer material that can slowly degrade under prolonged UV exposure, particularly if protective coatings wear down over time. This can lead to fading, micro-cracking and surface dullness after many years outdoors.

Stainless steel, by contrast, is not affected by ultraviolet light and won’t bleach or discolour in the sun, meaning it keeps its appearance for decades.

Beautiful with lighting

Stainless steel reflects water and lighting very well which can look particularly striking. With the right lighting, the water can take on different shades of blue, or any colour you prefer.

Surprisingly economical

Whilst hot tub heat loss happens through a variety of sources including surface evaporation and pipework heat loss, the insulation within the shell and the cover can make a big difference. Thanks to thick insulation around the steel structure, our customers often comment that stainless steel spas retain heat really well, helping keep running costs down.

To learn more, visit our benefits of stainless steel guide.

No Chance of Delamination

In cold resorts, most hotels and spa clubs are installing stainless steel spas now because they will happily hold hot water in cold ambient temperatures without causing long-term damage.

Most acrylic hot tubs are manufactured by vacuum-forming a thin acrylic sheet and reinforcing it with layers of fibreglass and resin. While this works well initially, over time the bonded layers can weaken due to frequent heating and cooling, chemical exposure or structural stress.

This process, known as delamination, can cause bubbling, cracking or loss of structural strength in the shell. It doesn’t happen to every tub, but it’s something we see over time with layered shells.

Our stainless steel spas are made from flat sheets as a single entity which cannot delaminate.

Why People Choose Acrylic Hot Tubs

Acrylic hot tubs are widely available and usually come with a lower initial price tag. For some people, especially those looking for a shorter‑term option, that’s enough.

Over time, though, acrylic can scratch, fade, discolour or delaminate. For anyone wanting a spa that feels like a permanent, high‑quality feature in their home or garden, stainless steel often ends up being the better long‑term choice.

Why Stainless Steel Resists Rust

Stainless steel contains chromium, which reacts with oxygen to form a thin protective oxide layer on the surface. This layer continuously repairs itself when exposed to oxygen, preventing rust from forming even in the most challenging environments.

At SpaFlo, we use AISI 316L stainless steel, a high‑grade material with 16-18% chromium and 10–14% nickel, to ensure exceptional durability and a premium finish.

Are There Any Downsides?

There are two main things to keep in mind:

Higher upfront cost

Stainless steel hot tubs cost more initially, but they offer far better long‑term value thanks to their lifespan and durability.

Potential for dents or scratches

Like any metal surface, stainless steel can dent or scratch if it’s not looked after. Using the right cleaning products and keeping the spa covered when not in use helps prevent this. In a worst case scenario (like dropping something very heavy on the spa) SpaFlo can rectify the issue and make the hot tub as good as new.

Which Option Is Right for You?

If you want a spa that looks luxurious, stays clean, performs well year-round, and offers long‑term value, a stainless steel hot tub is a fantastic choice.

Stainless steel is increasingly used in commercial spas, hotels and wellness centres because it combines durability with high hygiene standards. Stainless steel swimming pools are now common in UK & European luxury spa environments where long lifespan and minimal maintenance are important.

Feature	Stainless Steel	Acrylic
Lifespan	30–50+ years	10–15 years
UV resistance	Excellent	Moderate
Hygiene	Non-porous	Can scratch
Delamination risk	None	Possible
Maintenance	Low	Moderate
Upfront cost	Higher	Lower