Ahhhh, that makes more sense. And in that case, I still stand by my answer, lol. What ever the max temp gets to right now, is the hottest it will get. Temps will only drop from this point on.. You definitely won't be melting any snow outside.
Now when you say "stick out a mile compared to the neighbors houses" what do you mean. Because Im thinking that the tent is in the attic, being vented into the same space (attic) and not outside or underneath, just as you stated. But this "sticking out" concern makes me think you're venting it out of a window or somewhere that other people can see it.. Is that the case? Because if so, that's a completely different concern and is more of a stealth issue than a heat concern, lol. Sorry. Just trying to help.