Clearwater Spas RTB (reflective thermal barrier) insulation is 12% more energy efficient than spray foam insulation. Their rigid insulation panels, with double-sided foil, reflects and recycles the heat from the internal equipment keeping the cabinet warm and dry. With an insulation R-20 value, the RTB insulation system provides better energy efficiency than other spas. Their RTB insulation also contains natural salt borates which are undesirable to insects and rodents. The removable service panels on all sides provide for easy upgrades and maintenance. Other brands with spray foam spas are messy and costly to service.