One way to heat your hot tub is with a solar hot tub heater. Since hot tubs and Jacuzzis use a lot of energy, getting a solar heater will save you a nice chunk of change over time.
Along with any solar hot tub heater you get, it is important to also buy a good hot tub cover and/or solar heating pads to help you keep the heat in. A good hot tub cover is really necessary whether or not you decide to get the solar heater.
By using a solar jacuzzi heater, you will be saving electricity and helping to save the enviroment as well. It will take several years before you recoup the amount of money you have to spend on the solar heater but in the long run it will be a smart choice.