Energy Efficient Hot Tubs Hot Spring Spas are built with energy-efficiency in mind and are one of a handful of manufactures who actually test their spas to prove it. Hot Spring Spas has certified all models to the California Energy Commission (CEC) in accordance with California law.California law is more strict on energy consumption than most any other state. With California setting the standard for energy-efficient hot tubs, you can have peace of mind knowing that your spa is designed to keep operating costs low no matter where you live. You just can’t find a more energy-efficient hot tub.