Zero™-Shell Perimeter Insulation

---

The most effective way to insulate any structure is at the perimeter—the same principle used in residential and commercial construction. Homes aren’t filled solid with insulation; they’re insulated in the walls. Zero™-Shell Perimeter Insulation applies that same proven building-science logic to hot tub design.

Instead of encasing plumbing and equipment in spray foam, Zero™-Shell uses rigid, insulated perimeter panels backed with advanced materials that deliver superior thermal performance. These panels are designed to slow heat transfer through the sidewalls while supporting serviceability and structural integrity.

Where space is limited and performance matters, aerogel-enhanced insulation has become a premium solution in demanding applications—from commercial refrigeration and aerospace to electric-vehicle battery systems. Aerogel’s extremely low thermal conductivity and high insulating value allow thinner layers to deliver strong resistance to heat flow, making it a highly effective element in high-efficiency insulation systems.

Unlike many fully foamed spas that require venting of the equipment compartment (venting that allows valuable heat to escape outdoors), the perimeter-insulated design keeps equipment heat inside the insulated thermal envelope of the spa. As pumps, heaters, and plumbing move warm water and radiate heat, that energy is retained and contributes to overall heat retention rather than being wasted outside.

Traditional full-foam insulation can be thought of as having a well-insulated wall—but leaving the window open. Even if some parts are insulated well, venting and heat escape paths undermine performance. Zero™-Shell Perimeter Insulation instead forms a consistent thermal shell around the spa, capturing heat from every direction and reducing energy loss.

When paired with the Zero™ Frost Foundation, Zero™-Shell Perimeter Insulation delivers complete thermal protection—from the ground up and around the entire shell—using materials and methods proven in some of the most performance-critical applications on Earth.

The result: improved real-world efficiency, better heat retention, and an insulation strategy built on science, not compromises.