Our jetted tub is plugged into a conventional outlet mounted on the floor next to the tub, which is behind tiled and drywall/stud walls. To meet code, the builder left an opening in the drywall/stud wall directly behind one end of the tub, and covered the opening with a grill normally used for return air ducts. In conjunction with other remodeling, I've moved the location of this opening, and made it somewhat smaller (but still ample room to work on the electrical if the need ever arose). My question is this: did the builder use the return grill merely as a matter of convenience, or is there a general code requirement that the cover be vented since there is an electrical device (pump) running, which generates heat? If heat buildup is not a consideration, and the code makes no requirement that the opening be vented, I'll install a solid cover, which will look better.