Frequently Asked Questions (FAQ)

Short answer: Yes, only better. Long answer: When we were designing the original spa cover, we were mainly concerned with making it easy to use. The first covers we built had a thin layer of closed-cell foam about a quarter-inch thick that actually insulated as well as the typical rigid foam covers regardless of how thick their foam was. But when it rained water would pool up on top of our cover.

So we added an air chamber to keep it afloat. It worked, but rain still pooled around the edges. So we made the air chamber bigger to shed the rain. During testing, we discovered that the air chambers actually insulated better than the rigid foam covers. We also didn’t need any closed-cell foam.

The main reason the SpaCap spa covers insulate as well or better than foam is our hot tub covers start insulating right at the water surface. This is important since that’s what we want to keep warm. Rigid foam covers are trying to insulate the water from way up on top of the spa. See More below under ASTM Testing.

SpaCap Hot Tub Covers are made from top quality marine materials. Our Deluxe SpaCap in Sunbrella marine-grade fabric is the same material used on the most expensive yachts in the world. Sunbrella is quite literally the world standard in outdoor fabric. All vinyl, including the best quality Marine-grade, is rated by HOURS outdoors and Sunbrella is rated by years.

The air chambers and underside of the SpaCap Hot Tub Cover is a vinyl-coated fabric similar to that used for Achilles and Zodiac inflatable boats. It has a base polyester fabric that is then coated with vinyl on both sides. It is the same fabric used in commercial fertilizer bin tarps and commercial truck tarps.

That means the material can handle some of the harshest chemical environments. The stitching is the same weight thread used to make truck tarps. In twenty years, we have yet to see a SpaCap Hot Tub Cover come apart at the stitching. All in all, we build every SpaCap Cover as if it were going on our own hot tub. They are truly built to last and to look good for years to come!

The SpaCap Hot Tub Covers typically last ten to twelve years. Some much longer. Since the bottom of the cover rests right on the spa water, spa chemistry is important. If you test your spa water regularly and only add the chemicals you need, and leave the cover off for an hour or two to let the concentration dissipate, then your cover will last for years.

If you just like to dump chlorine into the spa after every time you use the hot tub and just throw the cover back on, then you’ll probably replace it more often. We have customers that buy a new cover every three years because they refuse to change and evidentially have money to burn. But we design them to last for years. Also, it’s important to note there are alternatives to Chlorine and Bromine that are much safer to use for you, your hot tub parts and our covers.

We’ll explain why our covers can handle the wind but first the facts:
In thirty years, not even one of these has ever blown away even in Hurricanes and Tornados.

The reason SpaCap Hot Tub Covers stay put no matter how strong the wind blows, is that they make a lousy wing. There is nothing rigid for the wind to use to create a lift!. Whereas foam hot tub covers that are too heavy to lift will still fly away, given enough wind.
Plus, since the SpaCap rests directly on the water’s surface, there is no air space under it that the wind can use to pop it off the hot tub. Given enough wind, a heavy rigid foam filled hot tub cover will start to lift off the spa due to negative pressure caused by airflow. Once that happens, the wind can rush into the airspace below that foam cover and push it up from the bottom, at which point you have “Lift Off” and your hot tub cover is on its’ way to parts unknown.

A customer in Kansas told us they saw a SpaCap on their local news. In a shot showing the devastation caused by a tornado, the camera panned past a SpaCapHot Tub Cover still sitting on top of its owner's spa despite the fact that most of the neighborhood was destroyed.

Yes, for as long as there have been swim spas, we have been building Swim Spa Covers.

SpaCap Hot Tub Covers handle snow better than any rigid foam filled spa cover ever could. When covered in snow, the typical rigid foam Spa Cover acts like a frozen bridge. When the snow gets too heavy, the rigid foam will sag or break. The SpaCap rests right on the surface of the water, so no matter how much snow accumulates, the SpaCap cover transfers all the weight evenly to the water. We have been selling the SpaCap Hot Tub Covers in snow country for years. These Hot Tub Covers have gone through world record snowfalls and to date, with thousands sold around the world, there has not been even one crushed by a snow load.

In fact one year in Denver they had a record snowfall that was crushing patio roofs and hot tub covers. So many in fact that as insurance adjusters went from house to house, they just started asking if people had a hot tub so they would add the cost of a new Hot Tub Cover to the damage estimate. But the homeowners that had SpaCap Hot Tub Covers didn’t need a new cover. When the adjusters found out that there was a cover that could handle six feet of snow without a problem, they started suggesting our covers to replace the rigid foam covers that had been destroyed.

Yes, SpaCap spa covers can handle hail. Even golf ball-sized hail that would damage cars. It’s no trick, really, since the SpaCap doesn’t have rigid foam. The SpaCap can give with the impact and come through the storm unmanaged. Please check out the video where we smack golf balls into both a rigid foam cover and a SpaCap.

R-value of a Three Bladder SpaCap System
Measurement Method
ASTM C-518 (the Heat Meter Method)
R-Value = 25.8 hr ft 2ºF/Btu

How does that compare to a rigid foam cover?
R-Value 2.68 Btu/hr ft2 of rigid foam cover that allows evaporative cooling between the water surface and the bottom of the foam. No rigid foam cover ever made, no matter what foam cover dealers claim ever insulates from the water surface. That means that no matter how thick the foam, every foam cover allows evaporation and condensation to go on under it, which actually causes the water to cool down like a radiator.

What fools people into thinking that their foam cover is doing a great job insulating is that snow will sit on top of it in the cold of winter. But that’s only because the moisture in the foam is frozen. Snow will sit just fine in a block of ice. In truth, your spa has to work harder because the steam rises up off the warm spa water, hits the bottom of the frozen hardcover, cools and condenses, falling back into the spa water below.

H.F.Poppendiek of Geoscience LTD a research and development organization. His specialties are heat transfer, fluid mechanics, electromagnetics, nuclear reactor physics and engineering, micrometeorology, and biophysics. Mr. Poppendiek holds a Ph.D. in Engineering from the University of California. He also has years of experience in the industry, working on projects as diverse as heat transfer for re-entry vehicles and nuclear propulsion.