Top 5 Best Hot Tub Insulation Types [Why Are They Good?]

By James Brockbank •  Updated: 02/22/21 •  13 min read

What are the best hot tub insulation types?

The best hot tub insulation types:

  1. Thermal Wrap
  2. Partial Foam
  3. Full Foam
  4. Multi-Density Foam
  5. FiberCor Insulation

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Check out my list of high-quality hot tub products to help keep your hot tub clean and running great all year long!

I recommend the ULTCOVER Waterproof Hot Tub Cover. To protect your spa!

No matter which method you opt for, your mind will be at ease with utility bills. Also, keeping it insulated is a must during the winter season. Most companies do not cover the insurance if your hot tub gets frozen due to user error.

If you are looking for a complete guide on hot tub insulation, the insulation types, and why it is necessary, don’t worry. I got you covered.

You will find all the information needed to insulate a hot tub in this article.

Let’s get started!

What is Hot Tub Insulation?

Hot tub insulation is the material inside the spa cabinet protecting it from the elements outside. Usually, the insulation covers the entire outer shell, the electrical components including the pumps and the control system, and the plumbing. Insulation is meant to protect the hot tub from losing heat and enforces the structural integrity of the spa.

Insulation literally means keeping something warm. This is what you want to do with your hot tub – keeping it warm.

Insulation in a hot tub works by trapping the energy inside of it. This will keep the already hot water hot for a longer time.

Although hot tubs are already insulated, you can add some more effective materials to them to keep the water warm with less energy use. Hot tubs that are not appropriately insulated use more energy, and in turn, you are left with high utility bills.

If you are having problems heating your hot tub, check out our full article on the subject for more information!

Benefits of Hot Tub Insulation

Insulating the hot tub consumes less energy and, therefore, you will receive lesser utility bills.

The structural components of your spa will last longer, and they will work better.

Overall the life span of your hot tub will increase.

Insulation is best for the safety of your hot tub during the winter season. Hot tub insulation gives a hand in increasing energy efficiency.
Cold air from the outside environment could not interfere with the temperature of the water. As a result, the water will stay warmer for a long time.

Check out this great article from about 9 ways to reduce your energy costs.

How to Insulate a Hot Tub

To insulate a hot tub you must first remove the side panels and check if the hot tub is in good working order with the cabinet clean of debris. Next, add your insulation of choice into the cabinet, this insulation could be shaped insulated panels, radiant barriers, spray foam kits, and rolled fiberglass insulation. The insulation should be as close to the hot tub shell as possible. Finally, ensure that the insulation is securely in place and add the side panels back onto the spa.

The insulation covers the pipes, heater, and pumps with some insulating material so that the heat cannot escape. You need to keep the heat inside the hot tub. This way, the extra heat generated by the heater and pumps will remain in the tub. It is also necessary to keep these components ventilated; otherwise, they might heat up, resulting in damage.

The method of insulation is quite simple. There are three simple steps to get the task done.

Begin with opening the sides of the hot tub. These sidewalls are secured with screws that can be unlatched easily using a screwdriver.

The second step is to fill the insulating material all around the hot water pipes and heaters. Sometimes it becomes impossible to differentiate between the hot and cold water pipes. In such a situation, you should turn the hot tub on. The pipes which pump hot water will become warm after some time, while the cold water pipes will remain cold.

In many cases, the sleeves have their own taped joints, so place it around the pipe, and it will get stuck in place effortlessly.

Wrap the insulating material all around the four walls of your hot tub. You need to be much more cautious in case you are using fiberglass insulation. You have to wear extra thick gloves and eye protection as well. To make the insulating material more efficient, make sure to place it in layers.

hot tub insulation2

I recommend a number of different types of insulation based on what you’re looking to achieve with your spa. Some of these products include thermal heat barriers, wool panels, spray foam, and fiberglass insulation. You can find these products on

  1. Thermal Heat Barriers
  2. Ceramic Fiber Insulation
  3. Expanding Foam
  4. Fiberglass Insulation

5 Best Types of Hot Tub Insulation

There are many different types of hot tub insulation. Some of them are very cheap, and thus they are not very efficient. Others are quite expensive, which provides not only insulation but also structural support to the components.

So many different types of insulation can be overwhelming for the owner. But to make it easy, I have come up with an overview of different types of insulating materials with their cost.

Some of the most common hot tub insulation includes FiberCor, Multi-layered insulation, and Full-foam.

These insulation types are not always related to what you can use after the hot tub has been manufactured. Often these types of insulation have been added to the spa during the manufacturing process. For example, FiberCor is a proprietary material developed by HotSpring.

For insulation, you can use after purchasing your spa, check out the recommended products above.

Insulation Type Used By Cost
Thermal Wrap Atera Spas $$$
Partial Foam Marquis Spas $
Full Foam Jacuzzi Hot Tubs $$
Multi-Density Foam Hot Spring Spas $$$$
FiberCor Hot Spring Spas $$$

1. Thermal Wrap

The thermal wrap is a kind of insulation, which is not much effective; still, it does the task. A thermal wrap or thermal blanket can be usually used in combination with partial foam. As it is not very effective, so thermal wrap insulation is commonly used in larger swim spas.

I need to get the temperature to 80 degrees in a swim spa while in a hot tub; 102 degrees is required. The thermal wrap can be insulated either on the inside or the outside. That’s how it reflects the heat in the tub, keeping the heat inside.

If your hot tub does not have any insulation, you can get this thermal wrap done. It is not commonly used as a significant insulating material. Rather thermal wrap is used in combination with other materials to increase their efficiency.

2. Partial Foam

Partial foam insulation refers to the filling of part of the cabinet. As it does not fill the whole cabinet, the heat can escape into the outside air.

If you are looking for an affordable insulating material with a good level of efficiency, go for partial foam. It is excellent to keep the hot tub insulated and far better than having no insulation.

This type of insulation is placed on the outer side of the hot tub. These foams can be rigid or sprayed-in, which are beneficial in supporting the spa’s functional components.

Although it is not an efficient insulating method, you can still install partial foam insulation in your hot tubs as it is cheaper and vulnerable to freezing. Consider it as the best option if you live in a warm climate region.

3. Full Foam

Full foam insulation is what you can call the proper, efficient insulation. As the name suggests, the cabinets are entirely filled with full-foam insulation. As it is much more efficient than partial foam insulation, it is quite expensive.

There is no chance of air escaping when the tub is fully foam insulated. The components of the tub also stay in place. Also, there are fewer chances of leakages and cracks. It makes the hot tub much more efficient.

Although it is expensive, it saves a lot of your money going into utility bills and maintenance. In short, the use of full-foam insulation lowers the cost of operating spas to a considerable level.

4. Multi-Density Foam

Multi-density foam is the best insulating material for hot tubs. It offers the lowest operating costs and provides the most significant energy efficiency. With all these benefits, it is the most expensive among them all.

I can guess from the name that foams of different densities are sprayed around the plumbing system in layers in this type of insulation. The higher density of the foam means better insulating power. Such high-density foams should be avoided in single-density foam spas as the foam expansion leads to severe damage to the cabinet.

A lot of labor work is required to install this type of insulation. This not only provides insulation but also structural support to the components of the hot tub.

5. FiberCor Insulation

FiberCor insulation is new. Like full-foam insulation, it completely fills the cabinets of the spa, but not with urethane foam. In FiberCor insulation, loose wool-like fibers are used. This material is better than urethane in the sense that it is almost four times denser than urethane.

FiberCor is really easy to remove. It keeps all the components in their place, thus lowering any potential damage to the hot tub.

There are many benefits of FiberCor. Since it is an inorganic material, it prevents the growth of mold and mildew. This wool fiber material can be reused and recycled, which means it is eco-friendly.

FiberCor is a proprietary product of Watkins Wellness hot tubs for more details about some of their great products.

Other Ways to Insulate a Hot Tub

Along with proper cabinet insulation, you can use some other ways to optimize your hot tub insulation. Remember, you are doing all that to lower the maintenance cost and increase energy efficiency.

Spa Cover

You need to get the spa cover customized according to the model of the spa you have. The spa cover should have high-density foam to provide insulation to the hot tub. The purpose of a spa cover is to retain the heat even when the tub is not in use.

The spa cover can be made to last longer by using a UV radiation-resistant cover.

I recommend the Porch Shield Square Hot Tub Cover to help protect your hot tub from the elements.

Hot Tub Blanket

This blanket is also known as a floating thermal blanket as it floats on the top of the water. It aims at preventing heat loss. You can use this along with your spa cover as it can extend the life of the cover.

Spa blankets can also be used inside the compartments. The goal is to prevent those components from freezing. If you live in a frigid climate, you should have a hot tub blanket to avoid freezing components such as the pumps or motherboard.

I recommend the In The Swim’s Thermal Blanket.

Spa Platform

A spa platform is a base that can be added below the spa to reduce its contact from the ground. Less contact with the ground limits the heat escape, thus keeps the water warm for a longer time.

I recommend the Diversitech Black Pad for pools and spas.

Pump Shroud

Typically, the spa generates some energy that is lost in the environment. As the spa runs, this heat is produced. You can make use of this heat by attaching a pump shroud. It works by capturing this surplus heat and transferring it to the water.

Also, it takes some cool air from the environment to cool down the pump. Thus preventing it from overheating.

Hot Tub Insulation for Winter (Why It’s Important)

It is necessary to add more and better insulation to your hot tub during the winter months. The hot tub can become frozen in the winter if it is not insulated well and adequately looked after. Therefore, always use a spa cover and spa blanket for better heat retention.

Winter is cold, and there is more heat dissipation than usual. This consumes more energy, and your utility bills can rise quite quickly if the hot tub is continuously trying to heat itself.

If your hot tub is already insulated, you can optimize it further by adding some more insulating accessories to keep the heat trapped and prevent it from escaping.

Besides cabinet insulation and spa covers, you can use a spa cover cap, spa cover wind straps, and protecta-spa cover.

Also, enclosing the hot tub in a gazebo will help protect the hot tub from the elements and debris.

Outdoor Spa Cover

It is a full hot tub cover that will prevent the hot tub from any damage caused by wind, rain, snow, and UV radiation. It doesn’t help in insulation but provides protection from low temperatures.

I recommend the ULTCOVER Waterproof Hot Tub Cover.

Spa Cover Wind Straps

These straps can be placed and attached over the spa cover to prevent it from being pushed upward in the wind. Strong wind can blow away heat with it; therefore, keeping the cover in place is necessary. The wind straps can be latched to tighten the cover.

I recommend a strong car cover wind strap for your hot tub.

Spa Cover Cap

It is a sheet that protects your spa cover. The cover cap will protect the spa cover from everything and increase its life span.

I recommend this hot tub cover cap from

Hot Tub Insulation: Conclusion

hot tub insulation

Insulation of the hot tub is crucial if you don’t want empty pockets. It’s like a one-time investment, which saves you from investing a lot in maintenance.

Along with insulation, various materials provide support to the components of the hot tub. You can choose any of these for your hot tub, from cheap thermal wrap insulation to the most expensive multi-density foam insulation. The higher the cost price of insulating material, the lower will be the maintenance and vice versa.

In addition to the cabinet insulation, you can add some other accessories to optimize the insulation. This includes spa cover, spa blankets, pump shroud, and spa platform.

Check out our full article on how long it takes to heat up a hot tub for more information on heating.

I hope this article on hot tub insulation was helpful.

Thanks for visiting

James Brockbank