Hot Tub Floating Thermal Blankets: Are They Worth It?

Jennifer Rhodes

By Jennifer Rhodes · Updated

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While it's often termed a blanket, it's not because it's designed to keep you warm. You don't wear a blanket in a hot tub after all! A hot tub blanket is a type of insulation blanket designed to sit on the water's surface, and hold the hot tub's heat in. But do they work?

The short answer is yes, hot tub floating thermal blankets are usually worth it. They provide several handy features that can make your hot tub more efficient, including reducing electric costs, extending longevity, and protecting hot tub components.

They're designed to hold the heat in the hot tub, which is essentially what provides all of these secondary benefits.

What is a hot tub blanket?

A hot tub blanket is a plastic sheet that floats on the water inside your hot tub. Of course, it's not just any plastic—it also has insulating properties. This usually comes in the form of little air bubbles, just like how bubble wrap is constructed. But you can also find foam varieties.

The goal is to stop water evaporating out of your hot tub so quickly, which reduces the load on your heater, in turn saving energy.

Did you know? When fitted correctly, a thermal blanket can reduce evaporation by up to 95%.

These blankets are much more popular in northern states where the winters especially can get pretty harsh, but that doesn't mean they have no uses in warmer climates. Keeping your tub more insulated is useful in these areas as well, especially in the winter months.

Floating hot tub blanket benefits

Everybody wants to save money, and hot tubs attack your checking account on several fronts—but top of many people's minds right now is the power bill.

Floating hot tub blankets can help out with this. For one thing, adding a blanket will help your hot tub retain more of its heat, meaning it has to work less hard to keep heating itself. Heat rises, and a hot tub with an open water surface allows the heat from the water to dissipate. Of course, if your cover seals properly, this is less of an issue. But many old or poorly constructed hot tub covers are not doing as good a job at this as they should be.

As long as the heat is bleeding off, the heating element has to run to keep the water at the right temperature. It's especially bad in the winter when running a hot tub comes at a premium. Heat bleed-off is much higher in the cold season.

Heat retention isn't the only benefit, however. You can also expect:

  • Increased energy efficiency
  • Reduced water loss through evaporation
  • Faster water heating
  • Less wear and tear on your pump and heater
  • Debris can't make its way into the water as easily

While the savings on your energy bill may amount to no more than a few dollars a month, that all adds up. And considering the fact that a hot tub thermal blanket only costs around $50-100, you could make up the cost in a single year.

What is the best hot tub blanket?

The best blanket depends on the material you want, plus the size and shape of your spa. Here are three great options.

Best overall: Spa Depot Thermo-Float 16mm Hot Tub Bubble Cover

Spa Depot Thermo-Float 16-mil 7ft x 7ft Hot Tub Bubble Cover
Spa Depot Thermo-Float 16-mil 7ft x 7ft Hot Tub Bubble Cover
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This cover is heavy-duty with a thick 16mm film, which means it's durable and reduces heat loss by up to 95%. It provides coverage for up to 7'x7' spas and can be trimmed to fit. It's a genuine ThermoFloat brand by Spa Depot, ensuring quality and performance.

Best for round spas: KETNET Solar Hot Tub Spa Bubble Cover

KETNET Solar Hot Tub Spa Bubble Cover Blanket for 6/7 Ft Round Inflatable Hot Tub
KETNET Solar Hot Tub Spa Bubble Cover Blanket for 6/7 Ft Round Inflatable Hot Tub
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If you have a round hot tub, this blanket will be perfect for you. It's designed to fit 6ft round hot tubs (though they also make a 7ft version). The thermal solar blanket helps retain heat and reduce evaporation, keeping your circular spa cozy and efficient.

Best foam: Spa Tender Floating Thermal Blanket

Spa Tender Floating Thermal Blanket 7x6' x 3/8-inch Closed Cell Foam
Spa Tender Floating Thermal Blanket 7x6' x 3/8-inch Closed Cell Foam
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For those seeking top-notch insulation or something a little more sturdy than bubble wrap, foam is a fantastic choice. This one is made of 3/8" closed-cell foam, making it the thickest in the market.

The foam blanket floats on your spa's water surface, significantly reducing heat loss and evaporation, which can lead to noticeable savings on energy bills. It's easily cut to size, fits most hot tubs, and works exceptionally well when used alongside a hard cover.

Should the bubbles face up or down?

A hot tub floating blanket should typically be placed with the bubbles facing down.

The purpose of these blankets is to help retain heat in the hot tub water and reduce heat loss to the environment. The bubbles on the underside of the blanket create a layer of insulation by trapping a layer of air between the bubbles and the water's surface. This helps to prevent heat from escaping through the water's surface and keeps the water temperature more stable.

So, to maximize the effectiveness of the hot tub floating blanket, make sure the bubble side is facing down and in direct contact with the water. This will help conserve energy and maintain the desired temperature in your hot tub.

Can you use hot tub floating blankets for indoor hot tubs?

You certainly can. While you don't have to worry about the same level of heat dissipation that you get from an outdoor hot tub, heat still dissipates. A hot tub thermal blanket will minimize the heat loss even more efficiently inside than it will outside.

While it probably won't provide you with the kind of power savings you get from an outdoor hot tub, it still makes a difference in the long run—not to mention that added layer of protection, keeping anything unnecessary out of the water.

How to maximize the efficiency of a hot tub blanket

Not only is a hot tub floating blanket a good idea for your spa, it's also more effective with a few additional components, especially with outdoor hot tubs in colder environments.

Trim it to size

Trimming a hot tub floating blanket to size is generally a good practice, and it can be important for several reasons:

  • Efficiency: Hot tub blankets are most effective when they cover the entire surface of the water without any gaps or excess material hanging over the sides. Trimming the blanket to fit the exact dimensions of your hot tub ensures that it provides maximum coverage and insulation, reducing heat loss and energy consumption.
  • Aesthetics: A neatly trimmed blanket gives your hot tub a cleaner and more organized appearance. It can improve the overall look of your hot tub area and create a more inviting atmosphere.

Add a jacket or cap

While jackets are more common with inflatable hot tubs, they are also effective with standard hot tubs if you can find one to fit. Adding a jacket, which completely encapsulates the entire hot tub, will boost the efficiency of a floating hot tub blanket by adding another layer of protection over the outer cover.

Hot tub caps on the other hand, only fit over the top of the hot tub. These are still effective at protecting your cover and reducing evaporation from the top, but will leave the sides uncovered.

Here are some of my favorites available on Amazon:

Add a mat for an inflatable spa

If your hot tub is inflatable, where you place it will determine its basic insulation efficiency. For instance, if you place it directly on the ground, it'll be directly exposed to the cold. Adding an insulating mat under the hot tub helps to insulate it from the cold starting from the bottom.

A great choice for round inflatable spas is the CosySpa Hot Tub Flooring Protector:

CosySpa Hot Tub Flooring Protector
CosySpa Hot Tub Flooring Protector
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Keep your blanket in good condition

Of course, regular maintenance is a must, especially when you're dealing with insulation blankets. A simple tear in the material is enough to drastically reduce the insulation properties, so you want to keep it clean and well maintained so it lasts the lifespan of the hot tub. Patch up and tears, and replace it if it's no longer holding its shape.

All things considered

Hot tub floating blankets are almost always worth the expense, especially since they aren't that expensive to begin with. They'll ultimately save you a good deal of money on your power and water consumption, as well as adding a layer of protection to the water.

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