The words “hot tub”, “spa”, and “jetted bathtub” are often used interchangeably to describe three very different products - in-ground spas, above-ground portable spas also known as hot tubs, and jetted bathtubs. Allow us to provide some clarification on the difference and nomenclature.
In-ground Spa
Not to be confused with a day spa, the term spa is often used to describe an in-ground spa. An in-ground spa is a body of water built into the ground, much like an in-ground pool. In residential settings, in-ground spas are usually built attached to the in-ground pool and are also what you are most likely to see at a hotel or gym. In-ground spas typically have a bench seat and a few jets built-in around the perimeter. They take a long time to heat up, and require a significant amount of energy to keep hot.
Hot Tub
Hot tub is typically used to refer to an above-ground portable spa. A hot tub or portable spa is a completely self-contained vessel. All of the plumbing, as well as the electrical control system and other components, are built inside the hot tub cabinet. This means that there is no plumbing required. A hot tub is filled with a garden hose, can be drained anytime, and can even be relocated to a new home if you move.
One of the best thing about hot tubs is their ability to hold a set temperature. Thanks to advancements in technology, you can set a selected temperature and expect your hot tub to be hot and ready to use anytime you are. There is no need to wait for the hot tub to heat up.
Hot tubs can range from very simple designs with a few jets, to intricate acrylic shells with an extremely high jet count. Hot tubs today have come a long way from the round redwood vessels of the past, and generally offer a much better experience than in-ground spas because they are more comfortable, more energy efficient, easier to care for, and provide better massage.
Jetted Bathtub
Much like Kleenex® and Xerox®, Jacuzzi® is a brand name that is sometimes incorrectly used as a generic term. The word "jacuzzi" is often heard when referring to an in-ground spa, a jetted bathtub, or an above ground portable spa or hot tub. The Jacuzzi brothers invented the first underwater jet, originally used in bathtubs, and called it a Jacuzzi jet. The Jacuzzi® brand today is a trademark for bathtubs as well as portable hot tubs - but since Jacuzzi® is a brand name, it's a good thing to remember that not every hot tub or jetted bathtub is a Jacuzzi® product.
In the world of warm water tubs, the terminology is perplexing. Many people don’t understand the difference between a hot tub and a Jacuzzi, or the difference between a Whirlpool and a spa. Although there are differences between them, they are so subtle and nuanced, it’s easy to confuse one with the other.
A hot tub is any large tub of warm water that can accommodate more than one person and is used for relaxation and entertainment. A Jacuzzi is a brand name of a company that manufactures hot tubs. In the US, the term spa refers to a hot tub with therapeutic jets.
It really is a whirlpool of information when it comes to defining the terms of warm water tubs. But we are here to let the bubbles settle and help you understand exactly what you should be calling that delicious warm bath you are soaking in.
4 Tell-Tale Traits to Determine the Tub Type
The chart below looks at the four key qualities that can help you determine what to call your tub. The tell-tale tub traits include whether it has jets, it’s inside or outside, it provides hydrotherapy and if it fits more than one or two people.
| HOT TUB | Yes | Some do and some don't | Mostly outside | Yes | 2-12 |
| JACUZZI | Yes | Yes | Mostly outside | Yes | 2-12 |
| SPA | Yes | Yes | Mostly outside | Yes | 2-12 |
| JETTED BATHTUB | No | Yes | Inside | Yes | 1-2 |
| WHIRLPOOL | Yes, but can also be a bathtub | Yes | Both | Yes | 1-2 or 2-12 |
| AIR TUB | No | Yes | Usually inside | Yes | 1-2 |
| SWIM SPA | No | Yes | Outside | Yes, it can be but often used for exercise | 1-5 |
| STOCK TANK POOL | Not typically, unless heater is added | Not typically, unless jets are added | Outside | No | 2-12 |
Let’s dig a little deeper and look at some key differences between these tubs:
A hot tub refers to any large tub or small pool of warm or hot water that can accommodate multiple people and is used for recreational purposes.
It can have jets, but this is not a defining feature. For example, a wood fire hot tub is not powered by electricity and is therefore only focused on warming the water without any massaging jets.
Hot tub is the umbrella term for all the other terms I’ll discuss in this post. A Jacuzzi, on the other hand, is a brand of hot tub.
The company’s early dominance in the industry of hot tubs meant that the name became synonymous with all hot tubs, but people are misusing the term.
Technically speaking, unless the hot tub was designed and produced by the trademarked company “Jacuzzi,” it’s not a Jacuzzi; it’s another brand of hot tub.
Jacuzzis vs Hot Tubs: Why the Mix-Up?
The fact that so many people still refer to hot tubs as Jacuzzis is a testament to the influence and impact this brand has had on the creation and popularity of hot tubs.
Several other brands have replaced their common noun descriptions, such as ChapStick, which should only reference the brand, not all lip ice or Xerox, which is a manufacturer of photocopiers, not a noun or verb to explain the process of photocopying.
In the 1970s, hot tubs became very much part of the social culture. In 1978 Jacuzzi became a trademarked brand name and officially should have brought an end to referring to any hot tub as a Jacuzzi.
However, even today, many people still call a hot tub a Jacuzzi, probably because the company remains at the forefront of luxury brands in this sector.
How to Tell a Hot Tub from a Spa
People have been making use of warm water bathing for hundreds of years. Ancient civilizations would make great journeys to reap the curative rewards of bathing in a natural spring.
The term spa comes from the Belgian town of Spa, which is renowned for its mineral-rich thermal waters.
In the US, the term spa is commonly used to describe a type of hot tub that includes strong water or air jets for therapeutic purposes. However, in Europe, spas refer to natural mineral springs and spa resorts.
A spa resort uses natural springs along with other water treatments and balneotherapy (technique of treating ailments through bathing) to heal their patrons.
Some of the earliest hot tubs were not the fancy designed pump systems of the Jacuzzi brothers but rather primitive large wooden wine vats with heated water.
As you can imagine, without a filtration system, these weren’t particularly sanitary.
When hot tubs began to gain popularity in the 1970s, manufacturers wanted to differentiate their indulgent products from these primitive, nasty wine barrels. This is why they coined the term spa based on the hydrotherapy practices that had long been associated with the word.
In the US, spas are jetted hot tubs.
Is a Hot Tub the Same as a Jetted Tub?
Technically, you can correctly refer to any hot tub with jets as a jetted tub. However, it is widely accepted that people are referring to a bathtub with hydrotherapy jets when referencing a jetted tub.
Unlike a hot tub, you typically drain a jetted tub after each use. For this reason, jetted tubs include a circulation pump but generally don’t have a filtration system like a hot tub will.
You will usually find a jetted bathtub indoors and it will usually fit only one or maybe two people.
While a hot tub can fit 2-12 people and is often found outdoors, you’re more likely to find a jetted tub in the primary bathroom.
(By the way, if you’re searching for a tub for your primary bathroom, read this post. We’ll recommend the best jetted and non-jetted tubs and what you need to consider when making your selection.)
Also, jetted tubs also don’t necessarily come with a water heater but, like a standard bathtub, they rely on the hot water from the boiler to produce warm water.
That said, there are devices to help keep your bath water in a jetted tub at the perfect temperature. (Read my blog about jetted tub heaters for more information.)
And if you’re looking for a more eco-friendly way to keep hot water on-demand for your jetted bath, consider installing a tankless water heater in the bathroom.
Is a Hot Tub Different from a Whirlpool Tub?
The term whirlpool made its first appearance in the world of hot tubs in 1968 when Jacuzzi described their integrated tub as such. Now, many people use the term “whirlpool” to describe both jetted bathtubs as well as hot tubs.
Of all the terms, “whirlpool” is the most applicable to any of the tub types.
The word “whirlpool” describes the motion the jets create as they swirl water in a circular motion in the tub.
One defining feature of a whirlpool is that it must have water jets (not air jets).
What Is an Air Tub? Is an Air Tub a Type of Hot Tub?
An air tub is a type of hot tub. But instead of pushing water through the jets to create the massaging effect like the Whirlpool, an air tub provides therapeutic massage with air.
The air creates more delicate,champagne-like bubbles that some people find more enjoyable than the forcefulness of water jets. Air tubs provide a gentle, all-over body rub as opposed to the targeted massage from water jets.
You can sometimes find a hot tub that combines air and water jets. These are usually called “combo” tubs. Jacuzzi makes a model they humorously call Aqualibrium.
If you want to learn more about whether an air tub could be right for you, read my post: Are Air Tubs Worth It? The Pros, the Cons & the Alternatives.
What Is a Swim Spa?
A swim spa is a small swimming pool, around 13 to 26 feet, that uses the jetted water system to create a continuous flow of water for resistance swimming. It allows a great workout in a small body of water as you remain in one place swimming against the current.
You can, of course, also use a swim spa as a small pool for recreational purposes. A swim spa will come with a heating system so you can enjoy warm water all year round.
Some models even have sections where one part is a traditional hot tub area and the other is for swimming.
What Is a Stock Tank Pool?
A stock tank pool is a shallow backyard pool made from a tank originally intended to feed animals on a farm.
While most stock tanks are 24 inches deep, they come in bathtub shapes with a 2-foot diameter, and circular shapes with a 6, 8, 10 and 12 foot diameters.
A stock tank pool is typically unheated and doesn’t contain jets, so it is neither considered a hot tub or a whirlpool. That said, you can turn a stock tank pool into a hot tub by adding a heater and transform a stock tank pool into a whirlpool by adding water jets.
For much more, read my post the 16 Biggest Pros and Cons of Stock Tank Pools.
Jacuzzi vs Hot Tub vs Spa!
If you find yourself sitting in a manufactured pool of warm water and you are unsure of what to call it, use the term hot tub; chances are you’ll be right.
Hot tub is the generic term for all recreational and hydrotherapy warm water tubs.
If you want to call it a Jacuzzi, everyone will know what you are referring to, but some smart alec might take pleasure in correcting and lecturing you on why that particular tub is not a Jacuzzi. To avoid this, look for the Jacuzzi branding; if it says it’s a Jacuzzi, then it’s a Jacuzzi.
If the tub has warm water and massaging jets, you can call it a spa, but if this is a bath in a bathroom, it’s best to refer to it as a jetted bath or whirlpool tub.
Feel free to call any spa tub a Whirlpool tub. All these words are somewhat interchangeable but follow the above formula to achieve the most accurate description of each.
Now that you know what to call it, you might be considering purchasing your own hot tub; we can help you choose the right one. Read how to buy a hot tub for tips that can literally save you thousands of dollars!
And once you have your hot tub, read This is How Hot YOUR Hot Tub Should Be, so you can enjoy it safely and prolong its longevity.