How Do Hot Tubs Work: Best #1 Guide for Beginners

By James Brockbank •  Updated: 02/11/21 •  9 min read

How do hot tubs work?

Hot tubs work by heating and circulating spa water in a controlled shell made of fiberglass, cement, or PVC (inflatable). Water is filtered and pressurized through pumps, pipe heaters, and water jets resulting in a relaxing environment.

Stop wasting time and money with hot tub maintenance and confusing water chemistry! The Hot Tub Handbook and Video Course will help keep your hot tub balanced, sanitized, and crystal clear all the time.

Check out my list of high-quality hot tub products to help keep your hot tub clean and running great all year long!

My recommended product to help you test your hot tub or pool water for accurate pH, alkalinity, bromine, and chlorine readings is the AquaCheck Trutest Digital Reader.

This article will discuss how hot tubs work in detail and what they are made out of.

Let’s get started!

How Do Hot Tubs Work?

The main reason I use hot tubs is to create a stress-reducing and relaxing environment. You may or may not have wondered how hot tubs work. Still, the basic operations lie in its mechanical construction and the design of its components. The answers to “how do hot tubs work” lie behind the mechanics of its main features, which I shall use to explain how the hot tub works.

First, you need to understand that water is held in the hot tub at the shell. The shell is molded to different seats. It is also installed with multiple jets and a layer of insulation on the underside to prevent heat loss.

Water is circulated in and out of the hot tub by using pumps. The pumps are also used to operate and filter the jets by controlling the pump speed. At low pressure, the pump produces a low speed that facilitates filtering and heating. You can control these parameters from your hot tub controls. High pressure on the pumps delivers high water pressure to the jets.

The massaging and the soothing effect you get when using the hot tubs result from the jet nozzles. The jets’ nozzles draw air to create a pressurized soothing effect in the hot tub.

The spa pack I mentioned above contains a heater and a controller. The controller helps each of the filters, the pump, jets, and heater to function as designed. Your spa heats up when the hot tub circulates water through the heater.

The hot tub filters help to maintain the clearness and cleanliness of the hot tub water. Finally, the topside controls allow you to change the water temperatures by controlling the water temperature and the lights, the pumps, and the blowers. It would be best to avoid letting the water temperatures exceed 104.

How are Hot Tubs Made?

Hot tubs are made from several different elements including cement, stainless steel, plastic, fiberglass, PVC (inflatable), wood, plastic, foam insulation, electrical components, plumbing materials, and other chemicals that bond the entire hot tub together. Speakers, flat-screen TVs, chlorine generators, and lighting are added later to make a completed hot tub.

You could be interested in knowing how the hot tubs’ numerous parts and features are brought together to produce the massaging and cooling experience. But the basic idea you need to know is that hot tubs have a shell designed to retain heat by staying insulated. The shell design contains a high multiple foam density that promotes durability and energy efficiency.

Your first step in making an acrylic hot tub is to rest a sheet of rigid acrylic over the hot tub’s mold.

You will then transfer acrylic into the oven. The bottom and the top’s heating elements will bake the sheet to render it malleable and soft. The sheet is then transferred to the mold again. At the mold, it is vacuum-sealed to give it the shape of the mold.

The acrylic sheet is then reinforced by applying fiberglass, resin, and paint. After taking out all the air pockets from the fiberglass, you will apply insulation on the underside. You will drill holes for the jets’ installation. Finally, the hoses, PVC tubing, the electrical elements, and the motor are installed.

What are Hot Tubs Made From?

You can use the following materials to make hot tubs:

To understand the question, “how do hot tubs work” much clearer, it’s essential to know the various materials used in its construction.

The Hot Tub Shell Materials

The kind of material you will choose for your hot tub shell will determine its strength when it comes to functionality and aesthetics. The primary function of the shell is to keep water within the hot tub. The choice of materials is critical in determining the amount of heat retained by your hot tub throughout its service life.

You can use different hot tub shell materials, but the most common ones are rotomolded plastic, acrylic, or vinyl. Traditionally, people could make hot tubs using wood. However, the material was less durable and sustainable.

Acrylic is the most common material for making the hot tub shell. You can make acrylic shells from single sheets and be reinforced with fiberglass and resin. Vinyl is also typical in making hot tubs. You can construct these materials by putting a vinyl liner over a frame of cement or other similar materials. Another option is the rotomolded plastic materials, which describe a plastic powder material with a dull matte finish and is very light in weight compared to acrylic.

Hot Tub Electrical

The electrical requirements are critical in helping answer your question, “how do hot tubs work?” You need to understand that hot tubs will require either 220V or 110V of electricity to run.

When you choose the 220V, it would be best to work with a certified electrician who will help you assess your electricity’s sufficiency in powering the spa. He/she will also do the wiring bit for you by linking your hot tub with your electrical panel. For the 110V, you can plug the hot tub into the electrical outlet in the backyard.

Get as much information as possible from the dealer to understand each of the two electrical configurations’ benefits and models’ limitations.

Different Hot Tub Components

hot tub parts

Below are the various components that make up a hot tub. These components include the shell, cabinet, jets, pump, filters, heater, and controller. We’ll briefly describe each one.

The Shell

This is the inner part of the hot tub surface made from acrylic or any other chemical or weather-resistant materials. The shell holds the hot tub water and contains different seats in its mold. You’ll also find the jet mounting points in the hot tub shells.

The Cabinet

The hot tub cabinet is the component that provides structural support for the equipment and the shell. It also hides the less aesthetic equipment like heaters, pumps, and plumbing behind the stylish doors. Cabinets are made of weather-resistant polymers that are easy to maintain.

Water Jets

Water jests are a favorite feature in a hot tub because they produce the bubbling effects that massage relieves any muscle soreness you might have. The jet’s nozzles draw air through its constricted section to create a pressurized effect, responsible for the pleasurable experience I get from the hot tub.

Check out our article on what to look for if your hot tub jets are not working properly.

The Pump

This component helps to circulate water inside and outside the hot tub. It also helps filter and operate the water jets by creating a low and a high speed when controlled at the spa pack button.

If you’re having problems with your hot tub pump, check out our full article on the subject for more information.

The Filters

Filters are the components responsible for keeping your hot tub clean and clear. The filters are located at an ideal location, accessible from the top of your hot tub. They have one or more screws and a skimmer. It would be best to keep the maximum filter efficiency by following the manufacturer’s guide in their maintenance.

Check out our full article on how to clean hot tub filters step by step!

Hot tub filters come in all shapes and sizes.

Our recommendation for larger filters is Guardian Pool/Spa filters.

Our recommendation for the smaller filters is Intex filters for inflatable hot tubs.

The Heater

The controller and the heater are contained in one pack or unit. The heater is the component responsible for heating water every time it circulates through it for every amount of each time.

Check out our article on how long it takes to heat a hot tub for some more great information!

I recommend the American Standard Safe-T Heater if you are looking to replace your hot tub heater.

The Controller

The controller unit allows safe pumping, filtering, heating, and jetting to function as designed. The controller allows you to control the hot tub from a generally easy-to-use control pad located somewhere on the hot tub.

The Cover

The cover is probably one of the most important parts of the hot tub. This is because it keeps the heat-insulated within the spa, keeps debris out, and protects the hot tub from being damaged when people are not using it.

If you have a large hard-sided hot tub, I recommend the SpaEase 100-2 Hot Tub Cover lift.

I also recommend the popular ULTCOVER Waterproof 600D Polyester Square Hot Tub Cover.

How Do Hot Tubs Work? Conclusion

how do hot tubs work

The hot tubs’ functionality depends on the various components and features and how they interact. I have seen that to understand hot tubs’ different parts, I need to know how they function.

Before you buy or make one, it’s also good to ensure that you know the hot tub’s electrical requirements. I have or use hot tubs as the primary reason for the pleasurable soothing and massage experience they generate. It’s essential to select suitable materials that balance aesthetic benefits with functionality and durability.

Most of the best hot tubs I know use acrylic materials. I hope this article has helped you answer the fundamental questions regarding how the hot tubs work. I shall keep you updated with other relevant information about these kinds of spas.

Here’s a great article from with some infographics about how hot tubs benefit everyone!

I hope you found this article on how do hot tubs work helpful.

Thanks for visiting

James Brockbank

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