Before answering this question, a quick note: Jacuzzi is a brand name today used to describe the product in general. Jacuzzis can be defined as hot water therapy environments that refer to a “hot tub” located in outdoor spaces or a jetted bathtub situated inside the home. In addition, jacuzzis often include hydrotherapy massage jets.
Now let’s see how it works: You can think of it as a small swimming pool. First, water is heated to a temperature of 104 degrees (at maximum!) with the help of an electric heating element. Then, the water temperature remains at this level for a long time, thanks to an efficient thermal protection layer provided by the insulation around the tub.
A circulation system allows the water to be sucked in and pushed out regularly so that the massaging effect is created. There is a pump and a paper-made filter in the circulation system, which is relatively small compared to the ones in swimming pools. Thanks to the return jets and therapy jets, water circulates in the design and is returned to the spa. This system is installed at the bottom of the jacuzzi: between the shell and the floor.
For this system to function, the water must be higher than the circular intake valve. The intake valve is usually located halfway between the rim and the base of the tub. The water is suctioned thanks to the vacuum power of the valve, and the screen attached to it prevents other objects in the tub (including fingers and toes!) from being drawn into the valves. As a complementary part of this circular process, water is expelled from the jets at varying pressure levels. The pump motors inside the system create this force. The number of pumps may vary in different jacuzzies. Jets are installed in the shell, and you can turn them on and off and control the water pressure with the help of the ring around them.
The pumping and spinning principles of a spa system are usually accompanied by an advanced temperature control system so that you can maintain the water temperature within the tub at the same level. However, this is often not the case with a jacuzzi. Since the water in the tub gets colder over time, you sometimes need to refill the tub with hot water, as in traditional bathtubs.
In some of the more advanced jacuzzies, there are also filtering and disinfecting systems. The filter system absorbs small dirt while the disinfecting system maintains the pH (acidity) level stable and kills bacteria in the water. Maintaining the chemical balance of the water stable, you can get clean, clear, and pH-neutral water for a long time.