Let me see, if I understand you correctly, you want to move your laundry upstairs and install it in a space currently occupied by a shower stall. If that's correct, is the shower stall located against an exterior wall? If not, will you be able to install vent ducting to the outside from there? A gas dryer doesn't pose a carbon monoxide hazard as long as it's properly vented to the outside. But, combustion byproducts are vented into the exhaust stream from the dryer drum and MUST be vented to the outside.

That being said, regardless of whether you choose a gas or an electric dryer, it will need to be vented to the outside, unless you choose one of the European condensor dryers. Without proper venting, an ordiary dryer would cause terrible problems with moisture and lint from the dryer exhaust. Dumping all that moisture into your living space will lead to mold and damp problems (not to mention the dust and lint). A very unhealthy and harmful situation. A bathroom exhaust fan is not sufficient ventilation to offset the heat and moisture generated by a dryer.

Unless you plan to leave the bathroom door open when the dryer is in operation, a louvered door is a good idea. Dryers move a large volume of air, all of which will be drawn from your living space and vented to the out of doors. All things considered, though, the louvered door is probably the least of your worries.

The next question is about power. Will you be able to get electricity and/or gas to that location? For an electric dryer you'll require a 220V electrical outlet for the dryer and a 120V outlet for the washer. If you elect to go with a gas dryer, then a single 120V duplex outlet will suffice, but you'll also need a gas line brought up to the new laundry location. Depending upon where your exisiting gas lines are in relation to the new laudry location -- this could get messy (walls would probably have to be opened up) and expensive.

Finally, there's the issue of water and waste plumbing. Most localities require a 2" standpipe for washer drains. Since most places also require a 2" drain line for showers, you should have adequate drainage available, but you'll need to demolish the shower floor then have a plumber remove the floor drain and reroute the drainline (and probably the drain vent) for the new standpipe. The shower mixer valve will also need to be removed and replaced with hose bibbs for the washer connection.

If you're still with me, you may be wondering if you still want to do this. While the project is certainly possible (provided you're able to install proper venting), it may not be as simple or as inexpensive as you might have been hoping.

Hope this helps.

Thanks,
Right now my kitchen, bathroom, and dining room are ripped down to the studs.
Adding gas and water lines is simple because the walls are open (there are none actually :) and this room is above a basement, so anything can come up through the floor.
Sounds like I should be ok with gas since I already have the Tromm (yes I was planning on cutting the hole to to vent to the outside.
Thanks for the detailed response...
Since I have just finished demo, would you keep the gas if you were me? I have to add the 220V plug or the gas line it has neither...Not even water since my pipes were so old.

Most places, gas dryers are still less expensive to operate than electric models. Otherwise, it's just a metter of personal preference. If it were me, and I had all the walls opened for a major renovation, I'd put in gas and keep my existing dryer -- but I'd also put in in a 220V electrical outlet, just in case I wanted to switch to an electric dryer somewhere down the road. In the greater scheme of things, it will cost very little to bring in the extra electrical service, and then all options are available.

If your house is of recent vintage, you might want to look into reinforcing the floor in the area under your laundry. In older houses (60+ years, or so), heavier lumber was used during construction, so you'd probably be fine (especially adjascent to a sturdy exterior wall), but in newer houses, some people have had trouble with vibration when installing laundries on second floors. The problem can be minimized by beefing up the floor in the laundry area.