AskCodeMan

Hey Jerry,
Is a window an acceptable means of providing makeup/combust air? I would assume that the vents should be permanent and who can say that the window will always be open?
Your thoughts
Marc

Got it, thanks Jerry

Hi Marc,

You are correct, a window which can be closed is not considered suitable for use as combustion makeup air.

The requirement is for minimum sizes of "openings" which connect spaces together or lead to the outdoor air, each opening would not be an "opening" if it was not always "open".

The window would be the same as putting a damper in an opening or duct for makeup air, the damper could be closed and thus the opening would no longer be an opening.