This boils down to the basic power of the tub, usually a 32-Amp would have two heaters/pumps, whilst a 13-amp will only have one heater or pump, A 13 Amp will generally designate it's power source to only one main individual component at any one time, meaning if the jets are on full pelt then the tub will automatically knock off the heater for a level of time to save on available power, while the 32 amp is built to run all components at once at any given time which makes for a better overall experience apart from having to install the electrics separately, Learn More