How does a hot tub work? Your complete guide

You’ve heard of hot tubs. You’ve seen them on the telly or in the movies. And you’re curious. But they don’t seem to make sense. How hard is it to keep water hot outside? Wouldn’t that cost a lot? What do you do in a hot tub once you have it?

By Jon Filson

Hydropool Hot Tubs and Swim Spas

Published Nov 20, 2023

You’ve heard of hot tubs. You’ve seen them on the telly or in the movies. 

And you’re curious. But they don’t seem to make sense. How hard is it to keep water hot outside? Wouldn’t that cost a lot? What do you do in a hot tub once you have it? 

They are fair questions. You’re not alone! Sometimes people come into our stores just to ask these questions. Sometimes they are halfway through buying and they start asking things like, “how does the cleaning system actually work?” 

We want people to know the answers to that question and all of their hot tub questions before they buy. That’s why we wrote this article, which explains the basic ways hot tubs function. That way you know what you’re getting when you buy a hot tub, rather than getting something you don’t really understand. 

In this article, we’re going to cover:

  • What is a hot tub?
  • What’s the difference between Jacuzzis, hot tubs and spas?
  • How is a hot tub heated?
  • How much power does a hot tub use?
  • How does a hot tub keep its water clean?
  • How is a hot tub built?
  • How to use a hot tub?

We hope that by the end you’ll have a strong sense of what that hot tub is actually doing before you decide to put one in your garden.

What is a hot tub?

A hot tub is any vessel filled with water, heated and used for relaxation, pleasure or wellness. The water jetted version of the hot tub was invented in the 1950s by the Jacuzzi family in California. Today hot tub models are now sold around the world and are commonplace as a personal luxury item and come with electric heaters to heat the water, powerful jets to circulate the water and create a massage effect and a filtration system to keep the tub clean. 

Hot tubs are generally square or rectangle, but there are some circles still being sold today. There are many types of tubs available, including inflatable, rotomold and acrylic, but about 80 per cent of them are made with acrylic shells on top of a wood or steel-framed cabinet and are powered by electricity. That most popular type is what Hydropool makes at its factory in Mississauga, Canada. 

What’s the difference between a Jacuzzi, a hot tub and a spa? 

These are all types of hot tubs and are often used interchangeably. Here’s a breakdown:

  • A Jacuzzi is a brand name. So all Jacuzzis are hot tubs, but all of them are not Jacuzzis. Think of it like this, as Hoover is to vacuums, Jacuzzi is to hot tubs.
  • A hot tub is a standard name for any water-holding container. They can be installed inside or outside, and come every which way, including portable hot tubs or wood-fired hot tubs to versions that are big enough to hold eight people.
  • A spa can mean many things. A spa can refer to a hot tub and often Americans refer to hot tubs as spas. Some areas call spas hot tubs which are installed directly in the ground and resemble actual pools. Or it can be a place where you get a manicure, a facial and a chance to relax.

How is a hot tub heated?

The simplest way to put it is that they are heated via a heater within its cabinet. There’s a lot going on underneath that cabinet:

  • There’s a heater, which is designed to warm your water and keep it warm.
  • There’s plumbing and hydrotherapy jets, which are designed to create water flow and massage while sitting in your tub.
  • There is at least one pump and sometimes more. The pump keeps your water moving, passing through the heater and through your sanitization system.
  • There is a decent level of insulation — on a good tub — which helps save you money by making the most of the heat your heater creates. Good insulation helps you be energy efficient.
  • There’s also a sanitization system, which keeps your water clean.
  • Lastly, there’s often a series of air hoses designed to pump air into your water, which helps compress it as it moves through the pipes, for stronger massage.

All of this is powered by an electrical circuit, either wired directly to your hot tub or through a plug-in, depending on what model you have. 

How much power does a hot tub use? 

We get asked questions like this we wrote an entire article about the monthly costs, which you can read here. It explains all the costs involved and how to be cost effective while owning a hot tub, which is usually where this conversation goes. 

In terms of power used, a tub uses about 3.5-6 kWh per day.  

How does a hot tub keep its water clean? 

There are two main ways hot tubs work to keep your water safe to sit in:

Filtration – This is exactly what it sounds like: filtering particles or substances out of your water, including leaves, dirt, perfume, moisturizer, shampoo, laundry detergent, you name it. Trace particles will get into your hot tub, and you need some way to get them out. That’s what a hot tub filter does.  

Sanitization – This is using chemicals to reduce anything like bacteria in your water. Similar water cleansing happens to our drinking water, to make it sanitary. 

Hydropool is known as a specialist in this area, with our self-cleaning system – watch a video about it here. It includes a PureWater system that uses UV and an oxidization process to further clean your water: Here’s a video on it! 

How is a hot tub built? 

They are assembled in factories around the world. 

  • Some are built in the countries they serve, to ensure they can handle the area climate (Hydropool is one of these: It’s built in Canada, so it’s built to withstand Canadian winters).
  • Some companies export their tubs around the world. Hydropool is also one of these: From our factory, we sell in more than 300 countries.
  • Some companies build in one place with head offices in another. For example, a company can be based in Canada, the U.S. or the UK and ship everything in from China, having had the tub built there. This is not how Hydropool does it.

In terms of what happens in those factories, there is more than one way to build:

  • Some companies assemble primarily by hand, with some robotic technology involved for precision. This would be Hydropool. We take a more bespoke approach and allow customization of our hot tubs.
  • Some companies use robots. What we see here is that companies lose the ability to customize, because robots just build one way. They do gain in cost savings, so they are able to build cheaper.

How to use a hot tub? 

There’s no science to this: get the water temperature the way you want it and hop in (you can adjust it afterwards as well as you like). Turn on the jets and find the massage if you’re up for it, but there’s nothing wrong with sitting in a vat of hot water at any time either. 

Some people also use tubs to work out in, although we’d recommend a swim spa for that. We encourage hot tub use for wellness reasons. 

Any tub you buy will have a manual in it, so you’ll know exactly what to do and how to run it. And if you buy from a local dealer, you will always have someone to ask questions when they come up. 

How does a hot tub work?  

The hot tub is an amazing invention that people have been using to feel better about themselves for decades now, ever since it was invented in the 1950s in California. It’s a vacation away while living in your garden. 

We get asked all sorts of questions about how they work, and we wrote this as a way of trying to answer everyone’s questions in one article. We broke down what’s in the cabinet, how it keeps warm, how it keeps its water clean and how it’s built. 

We hope that answered your questions, but we understand if we missed one or two! If we did, don’t hesitate to reach out to your local retailer with your query – you can find your dealer here

Jon Filson is the Senior Content Manager at Hydropool Hot Tubs and Swim Spas.