In theory this wil work, but it is risky. Will you be able to make sure that the tent gets closed everyday when the lights go off? If the tent is in a completely dark room
it won't matter.
In my grow box, even with the door open the HPS still heats it up pretty quick in there. Without my 4in inline fan venting the box, temps
would rocket to well over 100 degrees pretty quick.
I would suggest doing a test before getting plants into flower. And be sure you can commit to 60+ days of always closing the tent up.