Candy, why is it a problem how long it takes to dry? Are you getting mildew? Sealers help keep dirt out but are not effective at waterproofing grout. If your getting mildew on the tile as well as the grout, you probably need a bath fan (or if you have one, to run it longer). If there is mildew just on or in the grout, it's usually because the floor was not laid with sufficient slope to drain the water that always gets past the tile; or possibly the drain's weep holes are clogged. There's not much that can be done about these last two problems short of redoing the floor and pan. If mildew is not a problem and you just want the floor to dry faster for whatever reason, the window may be enough, but a good bath fan is probably better.