It is meant to increase relationships among Sims. Sims can do anything in it that they can in an ordinary hot tub, but while the candles are burning, social interactions between Sims in the tub are more likely to be accepted, and will have a larger effect. It has been reported that, if Sims "Try for Baby" while the candles are burning, it is more likely to result in a pregnancy.
The Love Tub's special properties last for four hours, and is signified by the burning candles. After that time, when the candles burn out, it functions as an ordinary hot tub.
Getting a Love Tub will fulfill the want to buy a hot tub.
Unlike the above-ground hot tub which is available in Buy mode, the Love Tub cannot be placed against a wall, fence, or railing.