Hot Tubs 101 Part One 110v Plug-In Tubs

What is a Plugin Hot Tub

Plugin tubs have the advantage of price and portability. Most plug-in tubs are very affordable and come in a wide variety and can be a great value. They do have some disadvantages, mainly the pump horsepower, heater wattage, and jet count. Because this type of tub plugs into a common 15amp wall outlet. This will limit how big the pump can be, normally no larger than 2hp, with 1hp and 1.5hp being the most common. The second is the heater. When plugged into an outlet, the heater, if it has one, runs at a very low wattage. In most hot tubs, the water is pushed through the heater when the pump runs at a low speed. The problem is when you want your jets on high speed, the heater will be turned off as you can not run both high speed and the heater at the same time. The exception to the first two problems is that some 110v spas run on 20 amps instead of 15 therefore the tub may have more power. Most of the time you have to hire an electrician to run a dedicated 20 amp line. The third disadvantage is the jets. Generally, these tubs have smaller jets as larger ones require more water pushed by the pump, which it cannot do. They also tend to have fewer jets, as the more you have, the less flow (pressure) you will have.


Plug-In Hot Tubs come in three types. Inflatable, roto mold, and standard shell with a subframe

Inflatable Hot Tubs

Inflatables can be the basic box store special or the soft tub brands found in Pool and Hot Tub stores. Inflatables you blow up with air, fill them with water, then plug into any outlet in the house. The biggest advantage of this type is you can drain it, move and set it up again or store it away until you need it again. The disadvantage is power consumption as many of these tubs don’t have a physical heater element, in many cases these tubs use the friction of the water passing through the pump as their heat source which is not very efficient. Unlike traditional hot tubs that house the equipment inside the frame, inflatables are kept in simple exterior housings that are more exposed, making them more likely to fail. Because it is inflated with air, there is no insulation to prevent heat loss. Lastly, you sit on the floor, which is not only not very relaxing but also your legs take up a lot of space, not leaving room for very many people.

Roto Mold Hot Tubs

The second type is roto mold. These hot tubs start off with a thermal plastic called high-density polyethylene. These beads are poured into a large rotating mold that heats the polyethylene into a complete hot tub as it rotates around in the mold. Both the inside shell and the subframe are all one piece. The main advantage here is cost. Unlike the inflatable tubs, these are more durable, cost less to make than the next type, and are lighter than the average hot tub. Just like inflatables, they lack horsepower, heater strength, can also be difficult to service or put a cover lifter on depending on the style.

Traditional Plugin Hot Tubs

The third type is the Shell with Sub Frame. This is the most common on the market and is made up of a separate shell set into a frame. As it is still a 110v spa, it has some of the same deficiencies as the first two. What you gain is a more traditional-looking and seating hot tub. The only drawback with any 110v spa is its smaller size. Due to the limit of the pump, 110v spas are not offered in larger sizes, as the pump is not big enough to move the water through the necessary amount of plumbing required for the size and jets.


The Most Common Hot Tubs Are 220 Volts

The majority of the hot tub industry is made up of tubs that run on 220 volts and will require special wiring like electric stoves, dryers, and other large appliances in your home. This segment of the hot tub market is very competitive with many manufacturers to choose from

A hot tub wired to 220v does not have any of the limits of its 110v cousins. They can be as big as you have room for, have as many jets and horsepower power as you want, run the heater at any speed. All kinds of features and add-ons to choose from. You can even get one you can swim in.

In the next chapter

 common elements of hot tub construction

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