What temperature should I keep my hot tub at in winter to prevent freezing?

For standby during severe cold, keep water 30–35 °C and enable freeze/anti-ice mode so the system circulates and heats automatically near 5 °C.

Can a hot tub freeze overnight?

Yes—especially in exposed, uninsulated tubs with low water levels and no circulation. Keep the cover sealed, maintain circulation, and monitor temperature.

How do I protect my hot tub during a power cut?

Keep the cover on, add thermal blankets, insulate the equipment bay and pipes. If the outage will last, drain the tub and blow out lines to prevent ice.

Should I drain my hot tub for the whole winter?

If you won’t use it for weeks, yes—drain, blow out lines, drain the heater and store pumps indoors. Otherwise keep circulating and covered.

Will a floating heater stop my hot tub from freezing?

A floating winter heater helps maintain a thawed surface and supports the main system, but it should be combined with a sealed cover and circulation.

Hot Tub Winter Freezing Prevention

Cold snaps can turn still water into ice fast — damaging shells, pipework, pumps and heaters. This guide shows you exactly how to prevent a hot tub from freezing with smart circulation, insulation, thermostat settings, and power-outage plans. New to winter spa care? Start with our winter hot tub care checklist and deep-dive into insulation tips.

Why Hot Tubs Freeze (and How to Stop It)

No circulation = cold spots inside the plumbing where ice forms first.
Exposed pipework and poor insulation lose heat quickly to wind and frost.
Power cuts or low thermostat settings let water drop below 0 °C.

Prevention focuses on moving water, retaining heat, and monitoring temperature. If you won’t use the tub for weeks, fully drain it safely and winterize.

Quick Checklist: Freeze Protection Essentials

Enable freeze/anti-ice mode (many systems circulate/heat automatically near 5 °C).
Keep water at a safe setpoint (typically 37–40 °C for use; 30–35 °C for standby during severe cold).
Run circulation daily and keep the cover tightly sealed.
Insulate cabinet voids, base and exposed pipework; add windbreaks.
Use a floating anti-freeze heater in extreme snaps: winter freeze prevention heater.

Step-by-Step: How to Prevent Freezing

Check cover & seals: A premium, insulated cover traps heat and limits evaporative cooling. Replace torn vapour barriers. See maintenance guide.
Enable freeze mode / timers: Set the controller to circulate when water nears 5 °C. For basic systems, schedule daily circulation blocks.
Set a safe temperature: In severe weather, avoid letting water fall below 30–35 °C. Lower only if you’ll supervise closely.
Improve insulation: Add rigid boards or foil-faced insulation to the cabinet (keeping clearances); insulate suction/return lines and the base. Tips in our insulation guide.
Add a floating heater (optional): Place a floating winter heater to keep a thawed zone and assist the main system.
Protect from wind: Fit temporary windbreaks (panels/hedges) to reduce convective losses.
Monitor remotely: If available, use app/alerts for temperature and fault codes during cold snaps.

Power Cut or Emergency? Do This

Keep the cover on and add thermal blankets (floating mats) under the cover.
Open equipment bay and wrap pipes with towels/blankets for temporary insulation.
Use the floating heater on a safe power source if the main system is down.
If prolonged outage is likely: drain shell and blow out lines (see winterizing steps below).

When You Won’t Use the Tub for Weeks

Fully winterize to avoid damage:

Power OFF → drain → blow out air/hydro lines → drain heater and pumps → dry the shell → store pumps indoors (−10 °C to +50 °C).
Detailed procedure: winter hot tub care.

Extra Efficiency Tips

Keep filters clean to ensure strong flow and even temperature.
Balance water chemistry (pH 7.2–7.8) to protect metals and seals — see water care options.
For wood-fired users, learn heat-up strategy vs electric: wood-fired vs electric and do wood-fired tubs need electricity?

Hot Tub Winter Freezing Prevention: Keep Your Spa Safe in Sub-Zero Weather