Foam covers soak up water the moment their vapor barrier fails — then get heavier every season until closing the spa is a two-person job. AIRCAP 1 replaces the foam with a sealed, welded air chamber. Nothing to soak into. Nothing to get heavy.
Every foam cover fails the same way.
A vinyl vapor barrier wraps a foam core. It holds — until steam, chemicals, or ordinary handling wear it thin. Once water gets in, it never leaves.
Already heavier than it needs to be, straight out of the box.
Owners of waterlogged covers routinely report triple-digit weight gains.
A saturated core that never fully dries is exactly what mildew wants.
No foam core means nothing to soak up.
AIRCAP 1 is built from welded drop-stitch fabric — the same construction behind premium inflatable paddleboards. Two layers held apart by thousands of internal threads, inflated, and fully sealed.
AirLoc™ sealed air chamber
No porous core, so there’s nothing for water to enter. The cover weighs the same in year three as day one.
Ziptech™ modular skirt
Three interchangeable skirt depths match your cabinet without a custom, weeks-long build order.
Patent-pending pressure relief
Valves manage the natural air expansion that comes with heat, so the shape holds under a hot tub’s daily swing.
AIRCAP 1 vs. a traditional foam cover
| Category | AIRCAP 1™ | Foam cover |
|---|---|---|
| Core | Sealed drop-stitch air chamber | Expanded polystyrene (EPS) foam |
| Moisture | Nothing porous to soak water in | Absorbs water once the barrier wears |
| Weight over time | Constant for the life of the cover | Climbs as moisture accumulates |
| Insulation over time | Holds steady as it ages | Falls off once wet |
| Sizing | Six standard sizes, ships now | Often custom-ordered, weeks to build |
| Typical lifespan | Outlasts foam; 3-yr warranty | 3–5 years before replacement |
Two ways to find your size.
Know your spa’s make & model?
Run it through thrml’s Spa Fitter tool and it matches you to the right AIRCAP 1 in seconds.
Prefer to measure?
SureFit walks you through measuring corner-to-corner, then places you in one of six sizes from 77″ to 94″.
Zip & go
Choose one of three Ziptech™ skirt depths, zip on, and you’re done — no waiting on a custom build.
Between sizes? Round up — a slightly larger AIRCAP overhangs by design; an undersized cover won’t seal at the edges.
Before you order
AIRCAP 1 covers square and rectangular spas from 77″ to 94″ across six sizes, with Ziptech™ skirts for the depth of your cabinet. Use the Spa Fitter or SureFit tool at thrmltech.com to confirm before ordering.
Correct — there’s no foam core to begin with. The panels are a sealed, welded drop-stitch air chamber coated in waterproof polyurethane, so there’s no porous material for water to get into.
The thousands of vertical threads inside the drop-stitch structure trap air when inflated, creating an insulating barrier — one that doesn’t fall off with age the way wet foam does.
Round up to the next size — a slightly larger AIRCAP overhangs the cabinet by design, which is how a spa cover is meant to sit.
3 years (36 months) from date of delivery against defects in materials and workmanship, under normal use.
Enter it at checkout on thrmltech.com after choosing your size — it takes $100 off, and free shipping is applied automatically.
$1,195 before the discount, and it’s the same price across all six sizes — use code HT_PEKL for $100 off + free shipping.
Stop lifting a cover that’s fighting you back.
Find your size and order the AIRCAP 1 directly from thrml.
