Spas usually have between one and four water pumps, with one circulation pump serving the heating and filtration water loop and the other(s) driving the hydrotherapy jets.

• 整体式热水浴缸通常比木制浴缸的宽度要窄，通常高度在80-95厘米（32"-36"），以便通过门和走廊/回廊/门厅/过道等。