What temperature should a hot tub be?
Quick answer
Most adults set a hot tub between 100 and 102°F. The widely accepted safety maximum is 104°F, and you should not exceed it. Go cooler (around 95 to 98°F) for children, during pregnancy, or with heart conditions, and limit soak time at the high end.
The right temperature is mostly comfort, inside a firm safety ceiling. Hot water raises your core temperature, so the hotter the set point, the shorter a safe soak.
Set points by who is soaking
- Typical adult soak: 100 to 102°F, comfortable for 15 to 30 minutes.
- The maximum: 104°F is the long-standing industry safety limit. Keep soaks short, stay hydrated, and get out if you feel lightheaded.
- Children: lower, around 95°F, and brief. Kids overheat faster than adults.
- Pregnancy or heart conditions: check with a doctor and keep it cooler, generally below 100°F, with short soaks.
Temperature and running cost
Heat loss rises with the gap between your water and the outdoor air, so every degree higher costs a little more to hold, more so in winter. If the bill matters, setting 100°F instead of 104°F trims standby loss with barely any change in comfort. The run-cost calculator shows the difference for your tub, and many owners turn the set point down a few degrees during long gaps between soaks.
Common questions
Is 104 degrees too hot?
It is the accepted maximum, not a target. Healthy adults can soak at 104F briefly, but it is the upper limit for a reason: core temperature climbs fast. Most people are more comfortable at 100 to 102F with a longer, safer soak.
Can I leave it lower to save money?
Yes. A lower set point loses less heat, so it costs less to hold. If you soak often, dropping a couple of degrees saves a little with no real loss of comfort; for long gaps, turning it down more saves more.
How long does it take to warm up after turning it down?
That depends on your gallons and heater. A wired tub recovers a few degrees in an hour or two; a plug-in tub is slower. The heat-time calculator will give you the number.