What is the best way to subdivide and heat a large room?
I was in a situation like this a while ago. I was also under a constraint where I could not make modifications of any kind (no nails, drilling, etc). So here is what I ended up doing.


Bought a bunch of C clamps. Since the room had open beam ceiling, I could use the clamps on the beams.
Put a clamp on every fourth or fifth beam so that the clamps were approximately 55 apart.
Went to a fabric store and bought several yards of the cheapest heavy fabric I could find. I also wanted something half way pleasent in appearance.
Cut the fabric in lengths that were the same as the height of the ceiling.
String rope (I used steel cable as it could be strong tighter) through the clamps.
Loop the ends of each piece of fabric over the rope and fasten the loop closed with safety pins.
Now you have a fabric divider for your room. It should keep warm air inside a section of the room.


With this method, you could have multiple layers of fabric for better insulation.