Some will like it cooler (98°–101°F) and others will like it hot (102°–104°). Hot tub systems have a manufacturer’s imposed maximum limit of 104 degrees Fahrenheit because according to medical experts, temperatures higher than 104°F can be hazardous to human health. Children should use a tub that is no hotter than 100 degrees. Pregnant women are typically advised by their medical providers to avoid hot tubs. Those with adverse health conditions, questions, or concerns should consult their medical provider. As for how cool the water can be, the gas and electric systems’ thermostat can be set as low as 50°. When it comes to deciding what the optimal temperature management is, it depends a lot on your usage frequency. It’s very possible that turning down the hot tub too much and too often could end up increasing the energy costs rather than decreasing them. It’s similar to your household heating system — if you drastically turn down your heat prior to leaving for a short trip of say two days, when you return your furnace could spend most of a day heating back up and in the end, it could have been more efficient to only turn your heat down slightly. But for a long trip of say two weeks or more, these inflection points and tradeoffs may lead to the opposite result where drastically decreasing the temperature does lead to an energy savings.  The other thing to consider with hot tub temperature management, especially if you don’t utilize the economy mode and/or WiFi capabilities to automate, is how long you will have to wait for it to heat back up to use the tub.  So, it varies based on your tub size, installation, climate, and usage habits. However, for the most part, tub owners use their tubs twice a week or more and hold the temperature in the high 80s or low 90s.