Spas are wonderful. Big electric bills are not. So we make sure our spas are totally insulated. While many spas claim to be fully foamed, they often use only cheaper, low-density, open-cell packaging-type foam. Hot Spring spas, by contrast, are totally insulated, not just fully foamed. The difference lies in our multiple layers of high-density, closed-cell polyurethane foam, the same material used to insulate commercial freezers. Once you own a Hot Spring spa, you'll really appreciate its lower operating costs.