mcp6453 wrote:
What kind of gas heater can be installed in a bedroom? I'm pretty
sure that an unvented one cannot. Since some bedrooms have gas
fireplace logs, there have to be some style of heater than will be
permitted under the code. I want a supplemental heater.

For vented heaters, can the vent open into the attic space, or does
it have to go all the way outside? The attic has open gables on each
end and a roof vent at the top.

I have a wall-mounted gas heater in my bedroom now, but I would never
run it while I'm asleep.

Why not? If you're paranoid, get a CO detector.

I grew up with natural gas space heaters and it didn't affect me [Look! A
Squirrel!].

It makes sense to not heat the whole house for 6-10 hours while you're
asleep, so heating only the bedroom is a good idea. There are alternatives,
however:
1. Wooly pajamas.
2. More blankets (worked for our pioneers).
3. Electric blanket.
4. More dogs.