Not all hot tubs are built alike...Two leading energy saving design features must be in every Hybrid hot tub to lower the energy costs as confirmed by independent testing at the California Polytechnic State University. The two features are maximizing the amount of insulation you put in the hot tub cavity, while minimizing the use of horsepower or motors to reduce the hot tub operation costs. The first feature necessary is our Eco4WALL™ Sealed Insulation Package (highlighted in yellow) . The second feature is the Beachcomber Energy Saver Management System (highlighted in green) .