Venting is tricky ... I'm REALLY hoping my ventilation works ..
I live in Florida and even with a $500 ventilation system in my attic it still gets up to around 130 - 150 degrees during the summer ... Guess where my hot air is going???
I'm venting right into my attic. For odor control I have a 6"X2' Odorsok that's splitting the two rooms.
https://www.rollitup.org/attachments/grow-room-design-setup/434603d1243826698-grow-room-beginnings-vegpower.jpg
Once I have purchased my fan it will point straight up into a 6' hole I will be cutting in the ceiling. It's going to be a TIGHT fit, but according to the math it should all fit.
So the air will go..
Room -> OdorSok -> HPS Hood -> Fan -> Attic -> Sofit Vents -> Outside
I seriously doubt that the air blowing off the 1000W HPS will warm up my already hot attic even the tiniest bit and theoretically I don't even need the OdorSok as it will be heavily diluted in the attic, but better safe than sorry IMO.
If you vent into a separate room I would instal a Ozone filter and then filter it through carbon and then out of the house (I feel the attic is the safest.)
If you go out a window I'd build a windowbox to keep any light from escaping and make it look as 'natural' as possilbe.
My room is incredibly small and I'm moving 440CFM out of it (roughly all the air out of the room 4 times a minute.) Right now I would focus on locating your space and working up from there. Your location makes a lot of decissions for you.
Remember for 4 HPS your going to need at least 15 amps PER LIGHT. Most household breakers are 15 amps for 10 outlets, so you might have to run some extra power to the room just for your HPS. You can get away with the regular power for air and water pumps, and what not. The HPS alone is like a oven or a fridge it yanks some serious power.
I have my 1000W going into a dedicated 20 amp outlet to cover everything plus surges. Then I have another 20 amp for everything else..
I've been planning since Dec and just started building last week. This takes SERIOUS time and plan correctly. I highly reccomend getting several grow books and reading everything you can her, it will help a lot!!
-RT76