Marquis Spas and Dimension One Spas feature solid foam insulation which prevents heat from escaping through the spa walls and base. The Spas Cover's are also insulated with the finest certified materials and includes a linear heat seal the entire length of the hinge where heat is most likely to escape. This will significantly reduce energy consumption to hold your operating costs at about $10 per month during the summer and approximately $30 per month in the winter. All of the spa models we carry have Energy Guides to allow you to see the expected operating costs and are much more energy efficient than the majority of spas made by other manufacturers. Compare and see!