Top Energy Performer at Cal Poly

The Coverplay test that helped lead to the Airframe Spa Cover.

The biggest opportunity to save energy in a hot tub isn’t hidden inside the equipment cabinet.

The surprising discovery was that the weakest energy link was the spa cover.

What if it’s the cover that was the problem?

That was a question inventor E. Jess Tudor was asking long before he created the Airframe Spa Cover.

His journey toward Airframe began with another invention: the Coverplay single-hinge compression design for a spa cover.

And in 2008, that idea was put to the test.

27 Spas. One Eye-Opening Energy Study

Researchers at Cal Poly San Luis Obispo tested 27 portable spas to measure how much electricity they used simply sitting hot and ready for use.

The results showed just how dramatically energy performance could vary from one spa to another.

In the study's original measured results, 16 of the 27 spas—nearly 60%—used more standby power than the allowable level used for comparison.

One of the standout performers was Spa V, fitted with Jess Tudor's Coverplay compression-angle cover.

Spa V held 350 gallons of water and had an allowable standby-power level of 248 watts and only used 136 watts.

Just 136 watts

That's approximately 45% below the allowable level.

When Cal Poly applied its temperature-normalization calculation, Spa V dropped to 105 watts—about 58% below the allowable level. Its test sheet specifically identifies a “Compression Angle Hinge,” with no Styrofoam cover dual hinge cap or hinge-fill material.

Why Did the Hinge Matter?

Think about your house in winter.

You can fill the walls with insulation, but if you leave the front door cracked open, heat still escapes.

A traditional folding spa cover can have a similar weak point.

The 2014 California utility CASE report explained that common double-hinge spa covers can create an insulation gap 1 to 3 inches wide running across the cover, allowing additional heat loss.

The report then pointed to the Coverplay single-hinge design as an example of a design that essentially eliminated that gap.

Even the original Cal Poly researchers saw enough potential in the idea to recommend additional testing using a Coverplay cover “which does not have a gap in the fill material at the hinge.”

That was an important clue:

A better spa cover could mean a more energy-efficient spa.

From Coverplay to Airframe

For Jess Tudor, the Coverplay test wasn't the finish line.

It was the beginning of the next idea.

Jess went on to invent the Airframe Spa Cover, taking what he had learned about hinges, sealing and heat loss and rethinking the spa cover from the inside out.

Instead of simply building another traditional foam cover, Airframe was engineered around the basic science of how heat escapes.

Conduction: Airframe uses chambered air to help slow heat traveling through the cover.

Convection: Its perimeter sealing system helps reduce warm air escaping around the spa.

Radiant heat: Radiant barriers within the Airframe help reduce another pathway for heat energy to escape.

And unlike a traditional foam core that can become heavier as it takes on moisture, Airframe is designed to remain lightweight, repairable and in service for the long term.

Why Does That Matter?

Because your spa heater has to replace the heat your spa loses.

Lose less heat, and there is less heat to replace.

That's why the cover deserves to be thought of as more than an accessory.

It's part of the spa's energy-management system.

In fact, the later California utility CASE report concluded that the spa cover likely offers the greatest opportunity for energy-efficiency improvement because it provides insulation while also helping seal the water surface and reduce evaporation.

One Test. A Better Idea. A New Kind of Spa Cover.

The CoverPlay single-hinge compression cover showed Jess Tudor that changing the way a spa cover manages heat could make a meaningful difference.

That lesson helped start the journey toward something even more ambitious:

Airframe.

A spa cover engineered not simply to cover hot water...

…but to help keep the energy you've already paid for inside your spa.

Airframe

Designed to Conserve. Engineered to Perform.

Discover the Airframe Difference →