Here’s what you need to know.

You’ve sat in a hot tub before. This coveted water-filled enclosure is heated to a toasty, therapeutic temperature for you to appreciate with family and friends. You’ve enjoyed its relaxing buoyancy and well-placed massage jets that caressed away worries while heat loosened tight muscles and eased sore joints. But have you ever wondered: How does a hot tub work? What does a hot tub do to bring you those delightful moments of wellbeing and improved health?

Let’s start with a summary of the major parts. 

A hot tub consists of:

  • Cabinet
  • Shell
  • Seating
  • Control system (or Spa Pack)
  • Pump
  • Hose system
  • Heating system
  • Water jets
  • Induction system
  • Air blower
  • Suction system
  • Filter
  • Ozonator (optional)
  • Cover
  • Steps

Now, let’s review the mechanics of how hot tubs work to keep water clear and running smoothly year round to provide jetted relief.  

Let’s begin with the exterior. The tub’s circular or rectangular cabinet often comes in a variety of colors and is commonly crafted from an aesthetically pleasing wood, stone, or brick, while the interior shell is usually vinyl, remodeled plastic, or acrylic (and less commonly stainless steel or cement). It’s sculpted and insulated interior lining is specifically designed to contain a large amount of water, retain heat, and fit users comfortably. A high-quality shell like acrylic with premium insulation will ensure your tub lasts the life of your spa as opposed to a less durable vinyl. Ergonomic seating to completely support your body and enable peak relaxation is an important part of the experience, whether via a lounge chair, captain’s chair, bench, or optional booster. 

Moving on to the electrical elements of a hot tub, the control system, well, controls everything it does—from amping up the heat, adjusting the jets, or turning on music or lights to provide ambiance for your experience or gathering. It is located either topside (on the edge of the tub) with most prefabricated hot tubs or spa side (away from the tub, near the pump, filter, and heater) with custom models. The latter can be operated conveniently with a remote.

When it comes to the plumbing of the tub, a strong pump is necessary for optimal performance. Once water is supplied from an exterior source, the pump impeller—rotating at a high RPM (revolutions per minute)—provides pressure via a hose system to an electric or gas heating system. This action stimulates the water molecules, causing them to move in a frenzied manner and create a higher temperature. 

Once at the desired heat, the water is then directed to strategically positioned interior water jets. An air induction system compresses the water stream from the jets and speeds it up, pulling in air to intensify the effects and produce an adjustable, targeted hydromassage for the desired body location (back, legs, arms, or feet). Often, an air blower also creates a profusion of bubbles for added therapeutic relief. 

hot tub diagram

At the same time, a suction system recycles the water so the process can be repeated again. As part of this inline or separate pump system, a cylindrical filter catches dirt and other pollutants in the folds of its replaceable cartridge to keep water pristine. (Note that some spa systems design their cartridge filter into the skimmer, before the pump, to prevent large debris from entering the tub; other spa owners opt to use ozonators to keep water clean—they are placed after the heating system and work by generating ozone gas, which is injected into the water to remove pollutants.) Insulated hot tub covers also ensure dirt and critters stay out of your spa, prevent almost 75% of water loss due to evaporation, and keep your system in top shape. 

While not usually included with your tub, don’t forget to add some steps so you can enter and exit your tub safely. 

If you have more questions about how hot tubs work, what hot tubs do, and why high-quality and energy-efficient models pay for themselves in the long run, we invite you to speak with one of our wellness specialists today. It’s never too late to invest in a lifetime of health and happiness for your family. 

family enjoying a hot tub at sunset

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