Choosing a hot tub heater will have a significant impact on your spa experience, so it is important to choose in relation to your hot tub preferences. Electric heaters are by far the most common and easiest heaters to install, though you can also use a wood-fired hot tub heater or a gas-powered hot tub heater. If the hot tub is near an electrical outlet that can support the required voltage of the heater, an electric heater is a convenient option, but keep in mind that it will drive up electric bills. A wood-fired heater is the least expensive to run, but it is also one of the least convenient.
An electric hot tub heater generally runs at either 120 volts or 240 volts, so it is important to check both the requirements for your hot tub and the outlet's ability to provide that much voltage to the heater. Incompatible units may damage the hot tub, so this is an important step in choosing the correct heater for your hot tub. If you are replacing an old hot tub heater, you can check the old heater for its specifications, which are usually written on the side of the unit.
A wood-fired heater is perfect for the camp hot tub. These types of heaters may either sit directly inside the water of the hot tub — which is efficient but will take up a significant amount of space in the tub — or it may sit outside the tub and feature a water exchange system. The water will essentially be pumped out of the tub, heated, and then pumped back into the tub. The regulation of the heat on wood-fired heaters is more difficult than electric heaters, and the heat is turned off when not in use, so it is less convenient than an electric heater. It is perfect, however, for a tub located somewhere an electrical outlet is not available, and it is the most eco-friendly of all the heating options.
A gas hot tub heater will use propane as the main power source for heating the tub. Gas units are attached to the outside of the hot tub, and the circulation system works similarly to some wood-fired heaters. The water is siphoned from the tub, heated, then circulated back into the tub. Gas heaters can be less expensive to run than electric heaters and they are more convenient than wood heaters, but they also take a fair amount of time to heat the water, and they too cannot be left on when the tub is not in use to prevent freezing water.