Thermal cover vs inflatable lid for an inflatable hot tub

What the standard lid does

On many Lay-Z-Spa and similar tubs, the lid is a PVC top that clips to the wall, with a separate inflatable bladder underneath. The bladder floats on the water and traps a layer of air, which slows heat loss and helps rain run off the domed top.

Intex PureSpa Deluxe models and some others use a foam cover instead. Foam covers are firmer and usually insulate better than an air bladder, but they are bulkier to store.

What a thermal cover adds

A thermal cover is usually a padded, insulated layer that fits over the whole tub, including the walls, often with a drawstring or straps at the base. It reduces heat lost through the side walls, which on an inflatable can be a large share of the total, and it shelters the tub from wind.

Makers say their thermal covers can cut energy use, and some listings quote a percentage. Treat such figures as the maker's claim; the real effect depends on the weather, how often the lid is off and how well it fits.

Side by side

Fit matters more than the brand

A thermal cover only works if it fits. Measure the outer diameter or length and width and the wall height, and choose the size the maker lists for your model. A loose cover lets wind in underneath; a tight one is hard to fit and wears at the seams. See our guide to hot tub cover sizes.

Always keep the pump unit's air vents clear. Some thermal covers have a cut out for the pump connections; others should stop short of them. Never cover the pump unit unless the maker says it is safe to do so.

Other ways to keep the heat in

Use our heat-up calculator to see the minimum kWh to heat your water; every bit of insulation reduces what the heater has to replace.

• Put an insulating ground mat or foam boards under the tub; much heat is lost through the floor.
• Shelter the tub from wind with a fence, screen or gazebo.
• Keep the bladder inflated firmly so it touches the water.
• Keep the lid on and clipped whenever the tub is not in use.
• Read our guide on how to insulate an inflatable hot tub.

Is a thermal cover worth it?

If you use the tub mainly in summer, the standard lid is usually enough. If you plan to keep it running through autumn and winter, a thermal cover is one of the simplest upgrades, alongside a good ground mat. If you are still choosing a tub, look at models with foam covers or insulated walls, as in our winter hot tub guide.

See premium tubs with better insulation →

Caring for either cover

Both covers last longer with simple care. Wipe the top and underside when you change the water, let them dry before storing, and keep them out of strong sun when the tub is packed away. Condensation on the underside of a thermal cover is normal; lift it and air it now and then so mildew does not take hold.

Check the clips, straps and seams every few weeks. A torn seam or a lost clip lets wind under the cover, and once wind gets in, heat loss climbs quickly. Our guides on cleaning a hot tub cover and securing a cover in wind go into more detail.

Frequently asked questions

Do I still need the inflatable lid with a thermal cover? Yes, in most set-ups. The thermal cover goes over the standard lid, not instead of it. Check your maker's instructions.

Can a thermal cover go over the pump? Only if the maker says so. The pump unit needs airflow, so keep its vents clear.

Will a thermal cover fit any brand? Not always. Sizes and wall heights differ, so match the cover to your tub's outer size and height.

Is a foam lid better than an inflatable lid? Foam lids usually insulate better and shed rain well, but they are bulkier to store and handle.