It seems odd that they would use wood doors instead of steel doors because steel doors couldn't be broken down, and would hold gas better. I would think the room would have to be air tight which wouldn't make sense if they had windows. I dont know if it is true or not, and I thought you guys could help. Thanks in advance!
/u/Sergey_Romanov has a post on their very useful blog about just this subject here:
What doors were actually used in the gas chambers of Auschwitz? The same as for the delousing chambers, i.e. the gas-tight ones. Notably, the delousing chambers in Auschwitz used wooden doors made gas-tight by felt stripes. Here is one such wooden gas-tight door in the delousing gas chamber of Block 1 in the main camp
They didn't have windows (some of them had side openings with small gas-tight doors for introducing Zyklon B, and those were secured with metal grating against the victims).
In addition to the link to my article posted above I also answered this here: https://www.reddit.com/r/AskHistorians/comments/d9uxdu/comment/f1lrl2b