How does a cold plunge chiller work?

The chiller is the heart of a self-cooling cold plunge. It is what lets you skip the ice and still get the same cold water every day. Here is what happens inside, in plain words.

The cooling loop

1. A pump draws water from the tub through the hoses.
2. The water passes a filter that catches hair, dust and particles.
3. Inside the chiller, a heat exchanger takes heat out of the water, the same principle as a fridge or an air conditioner.
4. The cooled water flows back into the tub, and the cycle repeats.

The heat that comes out of the water is released into the air around the chiller. That is why the chiller needs free air around it and does best in the shade.

Holding the temperature

You set your target in the Smart App, anywhere down to 3°C. On AirTub, cooling runs in Smart Cycles: the chiller cools until the target is reached, then pauses while the water keeps circulating through the filter. When the water has warmed by 3°C, cooling starts again. The result is cold, filtered water whenever you step in, without the chiller working all the time.

Flow monitoring and protection

A chiller must always have water flowing through it. AirTub monitors the flow and protects the chiller if it drops, for example when a filter is blocked or a valve is closed, which reduces the risk of damage and freezing inside the unit.

Power

Everything runs from a standard 220 V socket on a circuit with a residual-current device (RCD). AirTub Home uses a 365 W chiller for 1–8 people a day; AirTub Pro a 535 W chiller built for continuous use and up to 20 people a day. Compare them on the compare page.

Looking after your chiller

• Leave the factory settings alone. You only set the temperature and the schedule; the technical settings inside the controller should never be changed.
• Clean the internal washable filter on the back of the chiller about every 6 months. Close both tub valves first and keep towels ready, as a little water comes out.
• Once a year, have a qualified refrigeration or air-conditioning technician check it, with the power off and using dry compressed air only. Never use water, cleaning products or sprays on the chiller.
• Keep it ventilated, shaded and sheltered from direct rain.

Your manual has the step-by-step instructions, and our team helps you if anything is unclear.

Frequently asked questions

Is a cold plunge chiller noisy?

A modern compact chiller makes a low, steady hum while cooling and is quiet when it pauses. Place it where airflow is good rather than in a closed cupboard.

How long does it take to cool the water?

It depends on the starting water temperature, the air temperature and your target. After the first fill, the chiller usually needs 6–10 hours to reach your target. From then on it only has to hold the temperature, so the water is always ready.

Can I use ice to speed it up?

There is no need. The chiller does the cooling. See Cold plunge vs ice bath.