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How To Insulate An Inflatable Hot Tub – A Simple Guide

There are few luxuries quite as relaxing as setting up for a warm soak in an inflatable hot tub, but thanks to our unpredictable weather, keeping these things toasty isn’t always simple or cheap! To fix this, let’s look at how to insulate an inflatable hot tub.

If we’ve learned one thing during our ten years as hot tubbing experts, it’s that DIY and portable spas go hand in hand. Proper guidance makes improving your spa’s energy efficiency and heat retention more than possible, and insulation is the place to start!

How To Insulate An Inflatable Hot Tub In Winter

two pairs of feet in a hot tub surrounded by snow

There are a few ways to insulate an inflatable hot tub, the most effective being a combination of a ground sheet, a thermal jacket and an insulating cover during storage. Some spas even have built-in anti-icing units to help maintain their water temperature in the winter.

Add a ground mat

The first step to insulating an inflatable hot tub is to add a ground mat or foam sheet beneath the base. Measure the diameter of your spa and either cut a foam sheet to size or purchase a suitably-sized premade mat; this will prevent the spa’s heat from transferring to the ground.

Fit a thermal jacket

To insulate the walls, fit a thermal jacket to the shell of your hot tub. Many brands sell these products to be used with their specific models, though generic versions work just as well. They’ll even provide an extra layer of protection against punctures and scrapes! 

Use a secure cover

Attaching your spa’s secure cover during storage is also super important, as this will help trap the water’s heat, reducing your need to fire up the heaters daily. This can be improved further by placing a thermal blanket over the top of the cover.

Check for frost protection.

Some portable spas are fitted with frost protection systems, featuring automatic sensors that engage the heaters when the water drops below a certain temperature. Newer Lay-Z-Spas, MSpas and Cleverspas all have a version of this tech, so switch it on if you have it! 

What Is The Best Insulation For Hot Tubs?

The best insulation for hot tubs is to use a combination of a thick foam ground mat, and a good-quality thermal jacket and to fit an insulating blanket on top of your spa during storage.

In terms of materials, research shows you’ll see the best results using foam or Kingspan boards to build an insulating base, as both are lightweight, easy to manipulate and offer excellent thermal performance.

DIY Inflatable Hot Tub Insulation

tools laid together to spell DIY

Kingspan under a hot tub

To fit Kingspan insulation under your hot tub, you’ll need to purchase enough boards to cover the base completely and cut them down to size. It’s a good idea to place down a protective hot tub pad, then the insulation boards and then sit your hot tub on top.

Insulation board under 

Similar to Kingspan insulation, generic insulation boards can be purchased and cut down to fit the base of your hot tub. Some spa brands sell modular insulating tiles that can be connected to form a solid base.

Insulation jacket 

Insulation jackets simply slide over your hot tub. If your spa is manufactured by a popular brand like Lay-Z-Spa or Cleverspa, suitable jackets are sold via their web stores. For other models, just measure your spa’s diameter and find a jacket suited to a tub of that size.


How do you insulate a Lazy Spa?

To help maintain heat, all Lay-Z-Spas produced after 2021 come with Freeze Shield frost protection, which automatically warms the water if it ever drops below 6°C.

Older Lay-Z-Spas can be fitted with new Freeze Shield pumps. Just keep in mind that air jet models and hydro jet models have their own pumps, which cannot be used with the opposing style of Lay-Z-Spa.

Alongside using the Freeze Shield technology, it’s also a good idea to grab some floor protectors to fit under the base. Lay-Z-Spa sells its own insulating floor protectors that can be found on its website.

Last Word

Whether you opt for Kingspan thermal boards, an insulating jacket or a combination of the methods we’ve covered today, we hope you’ve learned that insulating your hot tub is a pretty straightforward job!

In our experience, the simplest and most effective route is to combine a thick foam mat with a hot tub pad and use a thermal cover over your spa during storage. Doing this can help to trap a surprising amount of heat and drastically reduce those hot tub energy bills

John Devlin

Hello, Welcome to my website. I’m John, and I created the InflatableHotTubGuide while researching these spas nearly a decade ago. Since its creation, the site has become the leading UK resource for many models. As a passionate hot tub user, I love to test and explore all the latest machines this industry keeps creating. I hope you find our content helpful.