The usual disclaimers apply here: Don't try this at home, I'm not responsible if you burn your house down, etc.
I don't leave the heater running when I'm not there. It wouldn't do any good anyway. It's a radiant heater meant to heat you directly, not the room.
The parts list is just what I used. You may want to try a different power supply since I ran into some issues with the one I picked.
Thanks for all the suggestions. Now that I've moved the reflectors away from the plastic, I don't have any more deformation even after hours of use. I'll put the files on thingiverse for people to use/modify.