Odor, with vapor, isn't nearly as much of a big deal as with smoke. It dissipates much quicker and doesn't smell anything like pot smoke. And like smoke (aside from sidestream smoke from joints), it depends on how much is exhaled, not the particular vape you're using. If you take a huge hit from a bong style vape, you're going to exhale a lot of vapor. Take a small hit that you can easily hold, and very little vapor will be exhaled.

For a dorm room I'd want a stealth unit, one that could easily double as an aromatherapy diffuser. The best one would be a Puple-Days. Without the 3 1/2" vapor tube, it's nothing but a diffuser. No digital display, no big glass wand or 3' of tubing to explain. It's also great for controlling your hits. No filling the room with vapor exhales. And you don't even have to spend $200. It's $150 delivered. And you get a beautiful piece of woodwork that's the most rugged electric vape on the market. And since it's a 12V design, you can run it 24/7, using only as much AC as a couple of night lights. It also comes with a car adapter-all you need for AC portable use.