How to inflate an inflatable hot tub properly

Before you inflate

Our full guide to setting up an inflatable hot tub covers the base, filling and first heat.

• Lay the tub on its ground cloth and any insulating mat on a clean, level base.
• Unroll it and let it warm up in the sun for a while if it is cold; PVC is stiffer when cold.
• Find the wall valve and check the seal is clean.
• Find the inflation hose and, if supplied, the pressure gauge.
• Read the inflation section in your manual for the right method and pressure.

Step by step with the pump unit

1. 1

   Connect the inflation hose to the air outlet on the pump unit, as your manual shows.

2. 2

   Open the wall valve and fit the other end of the hose.

3. 3

   Plug in the pump unit to a suitable socket with its RCD and switch it to inflate.

4. 4

   Watch the wall fill out; smooth the floor and walls as it rises.

5. 5

   Stop when the wall feels firm to a press or the gauge reaches the maker's figure.

6. 6

   Remove the hose quickly, close the valve and fit the cap.

7. 7

   Fit the pump unit to the tub's inlet and outlet, then fill with water.

Note:Do not leave the pump inflating unattended, and never over inflate. Too much pressure strains seams, especially as air expands in warm sun.

How firm should the wall be?

The wall should feel firm, like a well pumped exercise ball, but still give slightly when you press it hard. Some makers supply a gauge with a coloured band showing the correct pressure; use it if you have one. Too soft and the wall bows out when filled. Too hard and the seams take extra strain.

Air pressure rises in hot sun and falls in cold weather. If you inflate in the cool of the morning, the wall will feel firmer by afternoon. That is normal, but it is another reason not to over inflate at the start.

Topping up air during the season

Inflatable walls lose a little air over weeks, and more when the weather cools. Check firmness every week or two. To top up, connect the hose and add air in short bursts until the wall feels right again. Many owners do this with water in the tub and at normal temperature; follow your manual, as some say to do it before filling.

If you need to top up much more often than usual, you may have a slow leak. See inflatable hot tub losing water or air for how to find it.

Inflating without the pump unit

If the pump unit has failed or is away for repair, an electric air pump with a suitable adapter can inflate the wall, as long as it fits the valve. Watch it closely, as many electric pumps push air faster than the tub's own unit. Avoid high pressure compressors made for car tyres.

A manual foot or hand pump works too, but it is slow for a large tub. Whatever you use, stop at the firmness your manual describes. If you need a new pump unit, read replacing an inflatable hot tub pump.

Choosing a tub that holds its shape

Wall build affects how firm a tub feels and how well it holds air. Tubs with internal I-beam or Tritech style construction hold their shape well, while drop-stitch walls are firmer still. See drop-stitch vs standard walls and our premium inflatable hot tubs.

See premium tubs with firmer walls →

Frequently asked questions

Can you inflate a Lay-Z-Spa with water in it? Topping up air with water in is common, but follow your manual, as some models give a specific method. Never over inflate.

How do I inflate a Lay-Z-Spa without the pump? Use an electric air pump with an adapter that fits the valve, or a manual pump, and stop at the firmness the manual gives.

How do I know if I have over inflated it? The wall feels rock hard with no give and seams look stretched. Let a little air out through the valve.

Why does my tub feel softer in the morning? Cold air contracts. A wall that feels slightly soft on a cold morning often firms up as it warms.