Raypak 5.5kw 240v Electric Spa Heater When electricity is the energy choice Raypak is the quality choice -- dependable, trouble-free, performance-proven - with corrosion-free, 100% copper and bronze waterways. Two compact models - 5.5kw and 11kw - built to last by the company renowned for reliability. SpaPak spa/hot tub electric heaters furnish sustained heat to provide the maximum benefits of hydrotherapy...including stress reduction, relaxation and arthritis/pain relief.