How do walk-in bathtubs with built-in heaters maintain water temperature?

An inline heater on a walk-in bathtub helps maintain bathwater temperature while the circulation system operates. It generally does not replace the home's hot-water supply or fill a cold tub with instantly heated water. Check the model's heater rating, operating instructions and electrical requirements with the installer. Heated seats and backrests are separate features. Compare walk-in tub prices with the heater, electrical work and warranty included; there is no universal energy-saving percentage or standard lease price.