Ours in Broan Model 652, which looks like the above pictures. As Father Thomas wrote above, there are two slotted screws which go into the fan/light assembly. Those screws go through two keyhole slotted tabs which are part of the grill assembly. You'll need to shine a flashlight up into the fins to see them. In ours, the screws are 3-slots away from the "B" of both Broan badges. Loosen the screws enough so that the entire vent cover can rotate counterclockwise a little. This movement will align the screw heads with the wider opening of keyhole slotted tabs, thus allowing tabs to pass down over the screw heads, for removal of the grill assembly. From there, you can easily access the light bulb. To reassemble, align the screw heads with the larger opening of the keyhole slotted tabs, raise the assembly so that the screw heads pass through the tabs, then rotate the assembly a tiny bit clockwise so that the screws are aligned in the narrow ends of the slotted tabs. Tighten the screws enough to snug it up to the ceiling, but not so tight that it bends the aluminum. While you have the grill off, you might want to clean the fan and vent, which is fairly simple. Remove the 1/4" hex screw which is located near one of the long screws loosened to remove the grill. When the hex screw is removed, the entire fan/light module will swing down on a “hinge”. That motion results in unplugging the fan and light from the receptacle inside the 12X12 housing. Then slide the lowered fan/light module from the hinged peg, to completely remove the assembly from the housing.

Depends on how much work you are looking at. Is there power available in the ceiling at the fan location? Fishing concealed wiring in older houses is a crap shoot in mamy cases. Sometimes it goes smooth as can be, other times there are obstructions, and sometimes chopping opent he wall and ceiline to gain access are about the only way. Know you get to add in plaster reapair. Are the joists going in a convenient direction for the vent line? Running perpendicular to the joists is another big issue, and often requires major ceiling damage (and sometime re-enforcement of teh joists that are bored). Cutting brick is actually not hard at all. Spot the locatin by drilling from the inside out through the brick woth a 1/2 inch masonry bit in a hammer drill, then drill from outside in a rough circle and chisel out the material. A single hole (up to at least 8-10 inchs diameter) does not require a ledger or anything. A clean hole should take a couple hours at most.

I'm calling it a "steam shower" because we are going to have it totally enclosed rather than open at the top. But we are not installing a steam generator. I want to capture steam, but I don't like the steam pumping into the shower. I tried one and didn't like it, but I liked the steam building up in there when the generator was turned off. So we are going to have it built like a steam shower, with the sloped and tiled ceiling and the transom window and vent near that. On the vapor/waterproofing, I can't remember the names of the products right now. I've read all of the threads I can find on vapor barriers and waterproofing. I still need to follow up with tiler on which products he likes to use. He built my neighbor's shower and I watched him put a black sheet-type material on the studs, then the cement board, then the mesh tape and redguard, then the tile. After I talk to him again, I'll probably have some questions and I'll post them.

You can check amazon's or ebay for some units. You'll surely find a good unit at an affordable. price.