adding insulation to hot tub

If you love your hot tub but you can’t stand how much you have to pay for your energy bills each month, then it is likely that your hot tub isn’t as energy-efficient as it could be.

If you own an old or low-end hot tub, the hot tub insulation is probably subpar, bringing up your energy bills each month with the amount of energy it takes to heat your hot tub up.

The good thing is, adding insulation to a hot tub isn’t as difficult as you might think. Come dive in with us as we explore the ins and outs of how you can add insulation to your hot tub to make it more energy-efficient.

There are a couple of ways that you can insulate your hot tub.

For starters, if you want to add some extra insulation you can use spray insulation around the inside of the hot tub cabinet, which will trap in all of the heat that the pumps and heater generate.

Doing so will make your hot tub far more energy efficient, as it will make use of its own heat.

It is crucial to note that you should never overdo this, though.

Your pumps and heater need a bit of air so that they stay cool, otherwise, they could end up overheating and breaking. Be certain that you don’t block off any of the vents that are within your hot tub so that cool air from the outside can easily flow in.

Another way to retain heat in your hot tub without traditional forms of insulation is a floating thermal blanket. Plus, thermal floating blankets are very inexpensive, making them an excellent choice if you are on a budget.

Thermal heating blankets can reduce how much water evaporates from your hot tub, which will reduce the amount of heat that is lost. Water evaporation is a major culprit of heat loss, so having a thermal heating blanket at your disposal can help curb the problem.

When you buy a thermal heating blanket, place it on the surface of your spa water. It should lay flat. If it does not, cut it to size.

Step-By-Step Traditional Hot Tub Insulation

  • Open Your Cabinetry: The first thing that you will want to do is open the cabinets on your hot tub. You may have to have a screwdriver to do this, though some models allow the cabinets to lift right off without any additional tools.
  • Apply Your Insulation: Take your insulation and wrap it around your spa’s pipe system. If you can’t find where your heating pipes are at, turn your hot tub on and feel around for the ones that are warm. If the pipe remains cold when the hot tub is on, then it is a cold pipe and should not be wrapped.
  • Fill Your Cabinetry: Place your insulation around the inside of the cabinetry on all of the wall. It is important to layer it, though you should never compact your insulation.

In terms of the type of insulation that you should use, it is typically a good idea to use a mixture of spray foam insulation and traditional pink insulation. You may even want to place a radiant barrier on the backside of your hot tub’s panels.

Pink insulation works really nicely when attached to the back of wooden panels. You can simply staple it on to get it working. Just make sure that when you are applying this insulation, that you use gloves.

If you’re dealing with plastic panels, you may have to apply it with small screws so that it holds. The important thing is to make sure the screws aren’t so long that you drill them past the side panels of your hot tub.

What Do I Need To Insulate My Hot Tub?

There are a few things that we recommend buying if you want to insulate your hot tub, including:

  • Insulation Panels: You can pick up insulation panels from your local hardware store and buy them online. Just make sure to consider the size of the panels in relativity to the size of your hot tub. Do note that you can cut these panels if need be.
  • Spray Foam: Spray insulation helps you insulate those hard-to-reach areas
  • Rolled Fiberglass Insulation: When looking for rolled fiberglass insulation, try to go with the unfaced variety, which is the variety that does not have paper on the back of it. This paper is extremely flammable, and because your equipment in your hot tub gets quite hot, you should not have the paper sitting around it.
  • Radiant Barrier: A radiant barrier can be placed on the back of your insulation. The beauty of radiant barriers is that they are easy to cut to whatever size you need them.

What Type Of Insulation Is Best For Hot Tubs?

There are many kinds of spa insulation on the market. Different hot tub manufacturers use different kinds of insulation, including:

  • Multi-density foam
  • FiberCor Insulation
  • Barrier Insulation
  • Full and Partial foam insulation

Here are a few reason why we would recommend these different types of insulation

Partial Foam Insulation

This type of insulation is spray-on. You will partially spray this around the inside of your hot tub. It is seen pretty commonly in budget-friendly hot tubs. If you live in a warm climate, this should be sufficient.

Full Foam Insulation

This type of insulation is also spray-on and will be distributed throughout the entire interior of your hot tub.

Because it is “full-foam,” it will fill the entirety of your cabinet so that air is not able to leave it.

This kind of foam will also surround all of the equipment 

and piping in your hot tub, which prevents movement. We highly recommend full foam for colder climates, as it is some of the most energy-efficient around.

Barrier Insulation

Barrier insulation uses a spraying method, though it does not completely fill the hot tub’s interior, allowing air to travel through the hot tub cabinetry. A reflective foil barrier is typically placed on the back of the hot tub’s panels, which is much like the radiant barrier you would find in a standard attic.

FiberCor Insulation

FiberCor is the most costly compared to the other products listed here and is one of the newest insulation system products on the market today. Similar to a full foam hot tub, you will use this to fill inside the cabinet completely, meaning it will not allow heat to escape. However, the difference is that it is blown into your hot tub instead of sprayed on, meaning it does not harden within the hot tub’s interior.


Compared to barrier insulation, this is a bit more expensive. To apply it, you will spray it in multiple layers, each with its own thickness. The beauty of this type of insulation system stops heat loss, all while providing a bit of structural support. Yes, it will take more time to apply it and it will cost more, though if you want to protect your hot tub from heat loss in a cold climate, then it is the perfect product.

So, as you can see now, there are many different kinds of insulated hot tubs out there. It comes down to what level of energy efficiency you are looking for and how much you have to spend.

If you’re looking for something with high energy-efficiency that won’t break the bank, we highly recommend going with full-foam. If your budget isn’t something that you need to worry about, FiberCor is what we recommend.

Saving Money On My Energy Bill

It should be noted that, on average, a hot tub will add around $25 to your energy bill each month. This depends on the overall quality of your hot tub and how it was insulated.

Your energy bill cost will depend on a number of different factors, including:

  • The quality of your hot tub model
  • The energy-efficiency of your particular hot tub model
  • Whether or not you keep your spa cover on when you are not using your spa
  • If your spa is set to a consistent temperature all the time, as changing your temperature frequently can increase your bill.
  • How much electricity costs in your region

If your brother who is a hot tub owner in West Virginia has a pretty low electricity bill, it might not make sense to use that as a reference if you’re trying to determine your hot tub costs out in California. So, exactly how much electricity does a hot tub use?  Get a more detailed breakdown here.

Reducing Your Electricity Bill With a Hot Tub

The good thing is, there are a few ways that you can save money on your hot tub, including:

  • Turn It Off: If you don’t plan on using your hot tub for two weeks or more, you might consider turning it off.
  • Get A Quality Cover: If you don’t already have a quality, fitted cover for your hot tub, it is time to get one. It is even better if you can find a hot tub cover that locks in place.

  • Winterize: If you live in an area that gets extremely cold during the winters, you may considering winterizing your hot tub.
  • Program Your Hot Tub Cycles: You might live in an area where the electric company doesn’t charge as much during certain off-peak hours. If that is true in your case, you might consider programming your hot tub cycles so that it heats in that timeframe.
  • Clean Your Filter: If your filter is dirty or clogged, it will force your heater and pump to work much harder.

As you can see, there are a few easy things that you can do to save money and make the cost of hot tub ownership far less expensive.

One myth that we often hear is that you can lower your temperature after using your hot tub every time to save some cash. That is not true in the slightest. In fact, continually raising and lowering your hot tub temperature can amount to higher costs overall.

Insulating The Underside of Your Hot Tub

You might consider insulating the underside of your hot tub, even though it is not as efficient as making sure the inside of your cabinet is filled.

However, if your hot tub is placed on a wooden deck, for example, laying down some insulated material is a wonderful idea. Not only will it increase the overall energy efficiency of your hot tub, but it will also reduce the amount of noise that your hot tub makes and protect the wood on your deck.

Wooden decks often let sound seep between the slats where air passes through. Wood vibrates as well and tends to be quite noisy. We highly recommend getting a hot tub pad to place below your hot tub. Pair all of this with thermal blankets and you’ll have some of the best protection against heat loss on the market.

Do Thermal Blankets Work for Hot Tubs?

Thermal blankets, sometimes referred to as hot tub blankets, are wonderfully inexpensive investments that can help make sure you hot tub is well-insulated. They work in tandem with hot tub covers to keep air from escaping and keep the water from evaporating. Plus, you can also cut them so that they fit around the hot tub interior.

If you want to maintain the temperature the best way you can, we highly recommend getting one of these products.

Hot Tub Covers

Using a hot tub cover while heating up your hot tub is a must because they trap the heat inside.  If you’re not using one, your heating system is working harder to heat up the water, costing you more on energy bills.

If you don’t already have one, or are in the market for a new one, see The Cover Guy Reviews for the highest quality hot tub covers.


We hope that this article was helpful in providing tips to keep your hot tub related expenses as low as possible. Get yourself a quality hot tub cover, insulator material, and heating blanket, and you’ll be well on your way to cost-efficient hot tub ownership. 

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