How to insulate an inflatable hot tub

Where an inflatable tub loses heat

• The floor, sitting on cold ground or paving.
• The top, through the cover, especially if it is loose or sagging.
• The walls, air chambers with PVC skins rather than solid foam.
• Wind, which strips heat from every surface.
• Lid off time, every minute the cover is off.

Step 1: insulate the ground

A solid, level base comes first. On top of it, lay the ground cloth from the box and then an insulating layer. Many owners use interlocking foam floor tiles or a purpose made hot tub insulation mat. Some put rigid insulation boards under the mat on a slab.

Make sure the surface stays flat and firm so the tub does not sink unevenly when filled. Our base ideas page explains suitable bases.

Note:Keep all ground insulation clear of the pump unit's base and cables. Never let the pump unit stand in water.

Step 2: improve the cover

Keep the inflatable bladder or foam lid in good shape and the clips fastened. A sagging lid lets heat out and rain in. A thermal cover that wraps over the walls is the most effective single add-on for many tubs; see thermal cover vs inflatable lid.

Some owners add a floating thermal blanket on the water under the lid. It traps another layer of air at the surface. Lift it off before using the bubbles.

Step 3: shelter from wind

Wind is the hidden enemy. A fence, hedge, screen or a gazebo with side panels reduces heat loss noticeably on blustery days. Keep the tub away from the windiest corner of the garden if you can.

A shelter also keeps leaves and rain off, which helps water care. Check that any structure leaves space to lift the cover and access the pump unit.

Step 4: manage the pump unit

The pump unit contains the heater and needs airflow. Do not wrap it in blankets or put it in a sealed box. Some makers sell a pump cover designed for the unit; use only those approved by the maker.

Make sure hose connections are tight and insulated pipe sleeves, if your maker allows them, do not trap moisture. In freezing weather, follow the maker's frost guidance; see using an inflatable hot tub in winter.

Note:Hot tubs combine water and mains electricity. Use a weatherproof outdoor socket protected by an RCD, follow the maker's manual, and have any new circuit or socket fitted by a qualified electrician.

Habits that save heat

• Keep the lid on and clipped at all times when the tub is not in use.
• Turn bubbles off when you are not in the tub; they cool the water.
• Do not drop the set temperature very low and then reheat from cold each time; see should you leave a hot tub on all the time.
• Use our heat-up calculator to see the minimum kWh to heat your water.

If you are buying new

Some tubs are designed with better insulation from the start: drop-stitch or foam walls, foam lids and insulated floors. If you plan to use a tub through the winter, those features matter more than extra jets. See our winter tub guide.

See inflatable hot tubs for winter →

What not to do

Do not pack straw, blankets or loose insulation against the walls; they hold damp against the PVC and can trap water against the pump unit. Do not seal the tub inside a closed box or shed, as steam and electrics need ventilation. And do not run cables through insulation where they could be crushed or overheat.

Keep everything you add removable, so you can check the walls and seams for leaks and dry the tub properly when you pack it away.

Frequently asked questions

What is the best way to insulate an inflatable hot tub? An insulating ground mat and a thermal cover, plus wind shelter. Together they tackle the biggest sources of heat loss.

Can I put insulation around the walls? A thermal cover that wraps the walls is the usual way. Avoid anything that traps moisture against the PVC or blocks the pump unit.

Can I cover the pump unit to keep it warm? Only with a cover the maker approves. The unit needs airflow to work safely.

Does a floating blanket help? It can, by trapping air at the water surface under the lid. Remove it before using the bubbles.