I built a big igloo today to try out my skill and got it all done. Well the igloo turned out good, nice and roomy too. Then I got the idea to have a small fire inside which turned out good and bad.
The good is it melted the inside enough to coat the walls with ice which is good because it helps trap your body heat.
Now for the bad the igloo filled with smoke so I popped a hole out the side and top for a chimney this helped a bit but still wasn't sufficient to remove the smoke. My theory behind the fire is as long as there is complete combustion there should only be a little smoke. This proved to be wrong. Now if this was a survival situation starting a fire will boost the temp inside considerably and as long as you sit by the entrance there is plenty of fresh air so if necessary you could do this just be ready to be smoked out.