Portable spas have built-in (also called self-contained) equipment. They look like appliances. Like other hot tubs and spas, they have self-circulating systems. Portable spas appeal to people because it seems you can just buy it, plug it in, and go. No electrical hassle, no construction. The heaters on portable spas have about the same power as a hairdryer, only 1500 watts of output. Imagine heating 250 gallons of water with a hairdryer! In many cases turning on the pump that powers the jets turn off the heater. The name "portable" is somewhat misleading with some "portable spas" weighing 400-800 pounds empty!