family in backyard spa

Understanding Hot Tubs

In ancient times people created something like a hot tub by using calderas, in which they would place hot stones to heat the water. They have uncovered remains from wrecked marble bath tubs and pre-historic aquaducts from as far back as the 4th century in places like Therma. In ancient Japan they have used soaking tubs called ofuro, for centuries. The ancient Romans so loved their hot baths that the legionnaires would build their own baths at thermal and mineral springs during their long occupations in conquered lands. The fact that they’ve been around so long is a testament to how relaxing soaking in a hot water bath can be.

The first hot tubs began to show up in the USA in the nineteen forties inspired by the Japanese ofuro.  Hydrotherapy pumps were then added for the first time by Jacuzzi in the 50’s. Initially built with wood, manufacturers switched quickly to fiberglass and then more recently to using cast acrylic, polyethylene or another type of plastic to create their designs.

Whether you use the term hot tub, spa or jacuzzi to describe a large tub used for hydrotherapy, warmth, relaxation and of course lots of entertaining. The common factor is built in jets that are directed to the bathers to massage and smooth sore muscles.

Which hot tub type fits you best?

The first question to answer when considering a hot tub is which type is going to be the best for my situation and family. There are really just 2 main types of hot tubs:

  • Portable
  • In-ground – custom built

Portable models are the most common types for people to have at their homes. This is because they are not only cheaper but they also are manufactured in a single unit and can be placed and set up on a deck or back yard with ease. They typically will fit 2 to 8 adults. The cheapest models are inflatable and made of latex or vinyl. There are even some retro styles that are made of metal barrels or wood in case you’re looking for that 70’s vibe.

In-ground hot tubs (which are typically custom installations) are most commonly referred to as spas. Often these are built close to or attached to an in-ground swimming pool. These are pretty common at hotels that have swimming pools and many public pools will also have a spa.

In-ground spas are typically designed and build by a local pool and spa contractor to fit the outdoor (or indoor) space perfectly and to complement the landscaping. The cost for an in-ground hot tub installation will commonly be tens of thousands of dollars depending on the size and other factors.

Unfortunately, the word spa is also commonly used to refer to a health resort where people are pampered with massages and facials and such – with stays that can be just for a day or several nights. Due to that potential confusion it’s most common to use the word hot tub when referring to the large tub with jets of water in it.

What type of heater and insulation?

The next thing to consider is what type of heater the jacuzzi uses. Most modern tubs use either a natural gas or electric heater. Solar hot water systems can be used as well. There are even some wood fired hot tub heaters. Choose the heater type that is most convenient to your install location.

Good insulation in the tub will greatly increase it’s energy efficiency. Manufacturers use different methods for insulating their tubs and good comparable data can be hard to find. We recommend you ask the salesperson what types of insulation the tub uses and ask for any energy efficiency numbers available for the model of hot tub you’re looking at.

Get a cover

Regardless of the insulation around the tub itself, a hot tub loses most of it’s heat energy from the top of the water surface. A cover with even a small amount of R-value will reduce heating costs up to 75%, which can really add up.