Today, more and more families pursuing a higher quality of life are adding massage tubs to their bathroom upgrade lists. However, when shopping, they discover that prices for products that look similar can vary significantly. From basic Indoor bathtubs costing just $600 to $700 to high-end Outdoor hot tubs costing over $4000, what technical secrets and value propositions lie behind this enormous price gap?   1. Differences in Function and Performance Outdoor hot tubs utilize an intelligent heating and thermostatic system to maintain a constant water temperature at the optimal spa temperature. Conventional models often only offer basic heating.