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Can You Add Insulation to a Hot Tub? (Yes, here’s how & where)

So, you own a hot tub and love it, just like I do. But, your energy bill is higher than you wish it was. If you’re like me, you’ve probably wondered can you add insulation to a hot tub?

Yes, it’s not hard to add additional insulation to a hot tub. Less expensive hot tubs may have little to even no insulation, making them very energy inefficient. You can use a combination of rolled fiberglass, fiberglass panels, spray-on foam, and radiant barriers to significantly improve the energy-efficiency.

But that’s just a quick snapshot of the issue and the solution.

Can you somehow reduce your bill and make it lower while still using the hot tub regularly? Is it easy to add insulation to a hot tub? If so, what kind? Yes, hot tubs are usually well insulated as it is, but you can add additional insulation to it.

Will insulation help keep your hot tub warmer with less electricity?

Click here to read my ultimate guide on hot tub cost-saving measures. Insulation can also reduce how noisy your pump, blower, and heater are too.

So let’s dive in!

Ready to Spend Less Time On Maintenance and More Time Enjoying Your Hot Tub?

Let’s face it. Balancing the water, cleaning filters, dealing with rashes, and trying to figure out which chemicals to buy and add can make you feel more like a chemist than someone who just wants to relax after a long hard day!

That’s exactly why The Hot Tub Handbook and Video Course is so valuable!

This is from Matt over at Swim University and he developed it for people looking to save money, time, and frustration. His tips on chemicals can save you $100/year just by making sure you buy only what you need.

So if you’re ready to stop being confused or frustrated with your hot tub and start spending more time in it, check out The Hot Tub Handbook and Video Course.

Just click that link to learn more on their website.

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How can I insulate my hot tub?

There are a few ways to insulate your hot tub.

To add extra insulation, you can spray it around the hot tub’s cabinet to trap in the extra heat that is generated by the heater and pumps. This will make your hot tub more energy efficient. However, keep in mind to not overdo it.

Those pumps need some air to help keep them cooler, so they do not overheat and break. So, make sure you leave any vents in your cabinet open and not covered by anything, so it can get that fresh air in.

Floating thermal blankets are an easy and inexpensive way to help keep the heat in the hot tub.

They reduce the amount of evaporation of the water which helps reduce the heat loss from the water. Evaporation causes heat loss in the water, so using the thermal blankets on top of the water will help reduce this issue.

Thermal blankets go under the cover and float on the surface of the water. They are easy to cut to size (if needed), have great reviews, and are super easy to take on or off.

CLICK HERE to see my favorite one on Amazon.

If you are ready to insulate your hot tub, follow the steps below:

  • Open your hot tub’s cabinet sides, which may need to be unscrewed or may be easily lifted off.
  • Take the insulation and wrap it around the pipes that produce the hot water.
    • To find the heated pipes, run your hot tub, and find the ones that are warmed up.
    • Cold pipes will remain cold and never heat up, do not insulate these.
  • Put the insulation around the tub in the cabinet on all four of the walls. Layering it will help but make sure you do not compact it.

For the insulation itself, you may want to use a combination of the traditional pink insulation without the paper backing and spray foam. In addition to a radiant barrier on the backs of the panels.

The pink stuff works well when staple-gunned to the backside of (real) wood panels (paper side up). Just make sure to wear gloves when handling it.

A cordless drill and small screws work well for the plastic side panels that most hot tubs have today. Without the paper backing (which is better as the paper is flammable), you may need to use a small metal (or plastic) plate to screw into to hold the fiberglass in place

Just make sure the screws are short enough to not go all the way through to the outside.


Insulated panels – I really like this one from Rockwool on Amazon. It’s cheaper than Owens Corning and has a better rating too. Easy to cut with an Exacto knife.

Spray foam – Check out this Spray Foam on Amazon from DAP.

Rolled fiberglass insulation – I prefer the unfaced insulation which does NOT have a paper back. The paper backing is flammable, and should not be used near the equipment which can get hot.

Radiant Barrier – I like this waterproof thermal energy heat shield on Amazon. It’s easily cut to size, and could also be placed under the hot tub if you’re first setting it.

In this recent article, I dive deeper into how to add additional insulation to your hot tub. The article is geared towards making hot tubs quieter. But the same tips will improve energy efficiency and heat-loss too!

Just click that link to read it on my site.

What is the best insulation for a hot tub?

There are a variety of different kinds of insulation used in the manufacture of hot tubs.

Here’s a quick glance, with details below.

Kind of Insulation Used By Cost
Partial foam insulation Marquis Spas $
Full foam insulation Jacuzzi Hot Tubs $$
Barrier insulation Atera Spas $$$
FiberCor insulation Hot Spring Spas $$$
Multi-density foam Hot Spring Spas $$$$

It’s worth pointing out, however, that the manufacturers listed above may offer more than 1 kind of insulation, or offer upgrades for an additional price. The chart should not necessarily imply that one brand is better than another.

If you are in the purchasing phase, ask which of these kinds of insulation the hot tub you’re considering has. These are listed in order from least effective to most effective. Although any of the last 3 are good options:

  • Partial foam insulation
    • Spray-on foam is partially sprayed into the interior
    • Common with inexpensive hot tubs
    • Sufficient for warmer climates
  • Full foam insulation
    • Spray-on foam is completely sprayed into the interior
    • It fills the cabinet fully, allowing the air to no longer leave the cabinet.
    • The foam surrounds all pipes and equipment, preventing movement
    • This foam is energy-efficient and very effective.
  • Barrier insulation
    • Done with spray-on foam, but not completely filling the interior
    • Lets air pass through the cabinet.
    • Uses a reflective foil barrier on the backs of the panels similar to a radiant barrier you might put in your attic
  • FiberCor insulation
    • The most expensive of the four types listed here.
    • This insulation is new on the market, so most hot tub companies don’t offer this (yet)
    • Like full-foam, the entire interior gets filled
    • But the insulation is loose, and blown-in, rather than using spray-on foam which hardens
  • Multi-density full foam
    • Costs are a little higher than the barrier insulation.
    • Done by spraying in foam in layers of different thickness
    • Offers structural support in addition to helping with heat loss
    • Takes more time to put in your hot tub and is costly.

As you can see, there are different kinds of insulation you can use, based on what benefits you need and the cost of the insulation.

If you need cost-effective but still very energy-efficient, you should pick full foam. However, if the cost is not an issue, then FiberCor insulation is the way to go.

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How can I save my electric bill with a hot tub?

Hot tubs increase your energy bill by about $20-$30 a month (in most cases).

The cost of your hot tub’s electricity will depend on a few factors, such as:

  • The quality of the manufacturer
  • How energy-efficient your model is (the cheaper the hot tub, the lower the quality of insulation)
  • If you keep your cover on 100% of the time when not in use
  • If you keep your hot tub on 24/7 and set to a consistent temperature (frequent changes in temps or turning it off and on regularly will drive your bill higher)
  • The cost of electricity in your area

So even if your cousin in Texas has a decent energy bill, it may be different in Minnesota.

Here are some steps you can take to reduce your energy bill:

  • When your hot tub will not be in use for 2 or more weeks, lower your thermostat 5-10 degrees
  • Get a fitted hot tub cover that will completely cover your hot tub and lock in place.
  • When you are away from your home for a month or more, make sure you either turn off the hot tub if it is warm out or winterize your hot tub if it is cold out.
  • If your electric company charges less on off-peak hours, program your cycles to occur more during those hours
  • Insulate your hot tub cabinet.
  • Keep the filter clean. A clogged filter forces the pump and heater to work harder

These are just a few steps that can help you save money on your electric bill when you own a hot tub.

Many people think that lowering the temp after every use saves money.

In fact, that’s actually the opposite. Usually constantly lowering and raising the temperature will cost you more. However, as I outline in this recent article, there are some exceptions to that.

See them on my site by clicking that link.

Should I put insulation under my hot tub?

You can insulate underneath your hot tub, but the most efficient way to insulate is usually insulating your hot tub’s cabinet inside.

That being said, if you are putting your hot tub on a wooden deck, putting down some type of insulated mat is a great idea. Click here to read my ultimate guide on insulated pads under a hot tub.

It will help protect the deck. But it will also help your hot tub be less noisy.

After all, a wood deck not only lets sound pass between the slats, but the wood tends to amplify noise too.

So if that (what’s called a Spa Pad) sounds like it’s needed in your case, I like this one on Amazon. Just know that when you order 1, you 3 panels. And for most normal-sized hot tubs, you’ll likely need 6 panels total.

But back to insulating the inside of the hot tub.

It is more likely to lose heat there compared to underneath the hot tub. Using insulation inside the cabinet is a better way to keep the heat inside the hot tub. You can also use a floating thermal hot tub blanket to keep the heat in the water. These are all good ways to insulate your hot tub.

The good news is these thermal blankets are cheap on Amazon.

They can be cut to size if need be, but they also have several sizes available. CLICK HERE to see my favorite one on Amazon.

I mentioned noise above when talking about wood decks.

But a spa pas is only one of the ways to quiet a noisy hot tub. Luckily, in this recent article, I get into several ways to quiet your hot tub if you find it’s too loud when the heater or filter cycles kick in.

Just click that link to see it on my site.

Do hot tub blankets work?

Yes, is the short answer.

Hot tub blankets, also known as thermal floating blankets work by preventing heat loss due to evaporation. They are also great if your cover isn’t a high-quality one or if it’s getting a little worn out.

Lastly, they also work great if you live somewhere that gets really cold in winter.

However, it is usually better to use a high-quality hot tub cover that is secured to keep the hot water inside the hot tub. It needs to completely cover the hot tub while also being locked down.

But if you meet one of the conditions, I mention above, then CLICK HERE to see my favorite floating thermal blanket on Amazon. They can be cut to size (they come 8’x8′) and have fantastic reviews.

But how much will insulation help you in winter?

Depending on where you live, winter can significantly impact your hot tub heating costs. Click here to read my ultimate guide on hot tub winter cost-saving measures.

Final thoughts

Insulating your hot tub is a fairly common practice, even though hot tubs do come already insulated.

That’s even truer if the hot tub is $4,000 or less. Hot tubs in that price range, even from a reputable company, have less insulation. That’s one of the ways manufacturers can keep the prices lower on budget-friendly models.

For extra insulation, follow the steps above to keep the heat in your hot tub properly. It will help with your electric bill by requiring less work from the heater.

Not sure how much electricity you can save?

In this recent article, I get into all the details on hot tubs and how much electricity they use each month. So whether you haven’t bought one yet or want to know if your bill is in line, you’ll want to check it out.

Just click that link to read it on my site.

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Jeff Campbell