Do Floating Thermal Blankets Work?

I was skeptical about how effective a floating blanket would be for my hot tub, but I decided to take the risk and I’m so glad I did.

Hot tub thermal blankets work by conserving heat and reducing evaporation of water and chemicals by up to 95%. They reduce the amount of electricity needed by the spa, lowering running costs. Floating spa covers help to extend the life of the main cover, as well as other components housed within the hot tub.

Most hot tub owners assume that a floating blanket only serves to trap heat, but that’s just the beginning. There are so many other benefits that make purchasing one a no-brainer.

The benefits of a floating hot tub blanket

Floating thermal blankets, also known as bubble covers, are lightweight covers made from either translucent polythene or polypropylene. They’re suitable for hard-shell, plug-and-play, and inflatable hot tubs.

Having a snugly-fit blanket floating on the water’s surface is an effective insulator that dramatically reduces heat loss. In addition to reducing heat loss, the covers also warm the water.

By placing the bubbles downward in the water, heat is trapped inside the bubbles and transferred into the water, conserving and maintaining the temperature.

Thermal blanket covers come in a variety of different thickness grades, but the ideal thickness is 16-mil (500 microns), which is considered heavy-duty.

Heavy-duty thermal blankets are more expensive, but they are more thermally efficient, so don’t bother trying to save a few pennies by choosing a blanket thinner than 16-mil.

Savings on your energy bill

Hot tubs lose a tremendous amount of heat to the air, but you can prevent evaporation by up to 95% simply by using a floating thermal cover to insulate your hot tub.

The savings to your energy bill through decreased evaporation works out to approximately $5 per month.

But if you live in an area that is particularly cold, the insulation provided by the blanket will save you even more.

Floating blankets also reduce energy consumption by shortening the amount of time it takes to heat the water inside your hot tub.

They’re even able to stay floating on the water while you run the jets to evenly distribute the heat throughout your hot tub.

But saving $5 a month on your energy bill is just the tip of the iceberg.

Protect your main hot tub cover

If you’re serious about saving on your energy bills, then you’ll no doubt already have invested in an insulated hot tub cover.

As the warm water inside your spa evaporates and tries to escape, it’s blocked by the underside of the cover.

Unfortunately, the build-up of moisture accumulates beneath the cover, creating a humid environment that damages the underside.

The problem is further worsened by the fact that the moisture contains the chemicals you use to sanitize your spa.

The sanitizing chemicals cause even more damage, resulting in you having to replace the cover prematurely.

Having a floating blanket protects your main spa cover from excess moisture, which greatly prolongs its lifespan.

Less maintenance costs

Another benefit of having a floating spa blanket is less maintenance. Losing chemicals to evaporation means having to add extra. More chemicals mean more money.

You also won’t need to top up your spa with water quite so often either, so you’ll save on your water bill too.

Popping on the spa blanket on days when you’re in and out of the hot tub is a breeze because of how lightweight it is.

Doing so prevents falling leaves, dirt, and debris from finding their way into the spa water.

You won’t have to worry about the filters getting clogged up, so having your spa free of rubbish means less time cleaning.

I think by now you can see just how useful it is to invest in a simple floating cover. Whether you live in a hot or cold climate, the protection these blankets provide far outweighs their cost.

The only thing you need for installation is a pair of scissors. Simply trim the cover to match your hot tub shape, ensuring a snug fit around the borders to minimize heat loss.

Besides purchasing an inexpensive floating blanket, there are plenty of other things you can do to make your hot tub thermally efficient.

How can I make my hot tub more energy efficient?

The good news is that you can often reduce the running costs of your hot tub just with a bit of forethought and planning, with many of the changes being totally free. Let me show you.

Lower your hot tub’s temperature between uses

Hot tubs are designed to run all the time. The insulation makes it far more economical to maintain the temperature than to heat the water up from cold each time.

But one way you can reduce running costs is by lowering the temperature by 10°F (5°C) overnight between uses.

If you don’t use your spa all that often, you can even lower the temperature further, potentially saving a few hundred dollars per year by doing so.

However, it’s important to strike a balance between financial savings and practicality. The last thing you want is to have to wait hours for the water to heat up each time you fancy a soak.

And lowering by too much could even end up costing you more in the long run. For more information, check out my guide on the best practices for hot tub temperatures when not in use.

Insulated hot tub covers

Purchasing an insulated hot tub cover is the most effective way of making your spa more energy efficient.

The downside is that hot tub covers aren’t cheap and have a limited lifespan of 5 to 7 years. They deteriorate over time as the cover soaks up the moisture from the chemical-laden water.

But there is good news. Despite their cost, the huge decrease in your electricity bill will more than make up for the cost of the cover over its lifetime.

The trick to prolonging an insulated cover’s life is by combining it with a floating blanket that protects the cover from moisture absorption.

Even better, a floating blanket can increase the overall R-value by up to a third. Yes, the initial outlay on a cover is a lot, but there’s no doubt you’ll recoup on your investment.

Insulating jackets and caps

Insulating hot tub jackets and caps are another economical way to protect your spa and its components while lowering electricity usage.

Hot tub jackets

Hot tub jackets are made using quality insulating materials that completely enclose the spa on all four sides. They’re available for hard-shell, plug-and-play, and inflatable hot tubs.

Spa jackets are an absolute must for inflatable hot tubs that have very little in the way of insulation. They even cover the motor.

They’re handy if you use your hot tub during the wintertime when the components have to work extra hard to maintain the temperature.

A simple hot tub jacket can make life a lot easier for the pump and heater during cold weather, reducing the workload and prolonging their lifespan.

If you winterize your hot tub during the cold months, then a jacket is the perfect way to protect the panels from any unwanted animals or critters that decide to take up residence.

The last thing you want is to find your hot tub’s wiring has been chewed through when you come to open up again once the weather warms up.

Hot tub caps

Another option is hot tub caps. They’re fully waterproof and fit over the top of the spa’s main cover to act as a protective lid that provides extra insulation.

But they also have other benefits such as protecting from UV rays, rain, and snow, which all contribute toward prolonging the lifespan of your expensive cover.

Insulating foam

Budget hot tub models often lack the insulation of more expensive models. Adding insulation spray foamOpens in a new tab. to the cabinets of your hot tub is a simple way to reduce running costs.

Insulating foam can be sprayed inside the hot tub’s cabinet to trap the heat that is generated by the heater and pumps.

By the way, before you add the foam, tighten up any loose fittings in the plumbing.

If your spa already has good insulation, look to fill any cracks that have appeared to prevent unnecessary heat loss.

If you’ve not yet purchased a hot tub, it’s a good idea to spend a little more on a model with thermally efficient insulation. As a minimum, look for spas that come with full-foam insulation.

Insulating mats

Ensure that your hot tub is sat on concrete or a similarly hard surface as it creates extra thermal insulation.

You can further improve heat loss from the base by using these double-sided, non-slip puzzle matsOpens in a new tab.. I recommend purchasing the 1-inch (25ml) thick version for maximum insulation.

The mats are made from high-density EVA foam and simply interlock together to hold in as much heat as possible.

The great thing is that they also help reduce the amount of noise that comes from your spa. The constant hum of a hot tub can be a real nuisance for you and your neighbors, so kill two birds with one stone.

Regular maintenance routine

The condition of your hot tub components has a huge effect on its overall thermal efficiency.

It’ll come as no surprise to learn that the better condition your heater and pump are in, the more efficient they’ll be at heating the water.

But something I doubt you’ll have thought of is how the condition of the jets and filters contribute.

Running the jets while you’re heating the water is a good idea to evenly distribute the heat, so keeping the jets in good working order is key.

And when the filters are kept clean, the water is able to flow freely. This increases the thermal efficiency and reduces the time that it takes to heat the hot tub up.

If you’re no longer able to get your filters clean using filter cleanerOpens in a new tab., then it’s time to replace them. Trying to save a few pennies using old filters will end up costing you more in the long run.


The position of your hot tub plays a big role in how thermally efficient it is. Where possible, avoid windy spots in your yard so that the heater doesn’t have to work so hard because of the heat loss.

Something you may not have realized is that there’s often an increase in wind at the corner of your house. Creating some sort of enclosure using a windbreak or gazebo is a simple way to reduce heat loss.

Positioning a hot tub against a wall or fence that receives a lot of sun will transfer the heat that is absorbed to your hot tub, providing extra insulation.

Joshua Milton

Joshua Milton is a seasoned hot tub enthusiast. With many years of experience in the industry, he offers valuable insights on hot tub maintenance, health benefits, and relaxation techniques.

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