You will most likely need a/c , controlling the temp in there will be hard especially with 15 to 20 lights.

How are you hanging your lights? they will need to be on a pulley system with a roof that tall.

Another thing to think about is light reflection off the walls could paint or use white poly.

Yes the lights will be hang on pulleys. I'm thinking hang the lights 12' on 2x6 framing. The veg room will be enclosed. The entire rooms will be covered in white poly. Each room will have a 12" exhaust fan. Will window mount AC be sufficient? It's going to be a massive electric bill for sure.

A window a/c isn't going to do much for your situation.

traditional 1000w hps put off 3,400 btu of heat. With de bulbs it may be more. Multiply that by how many bulbs. Then factor in ambient temp. And ballasts, if they're mounted in the room. The 12" exhausts will help a lot. But you're still going to need a multiple-ton ac.
I'm no expert, but there are several hvac tradesmen around on the forum, as well as some threads for sizing ac.

Window ac def wont be enough. You will need very large a/c units one or 2 in each room, like savage mentioned i do not know the specifics of the actual requirements for a room that size.

As far as your exhausts go be careful of smell i have charcoal filters on all my exhausts.

You should also look into fresh air intakes as well.

Are you using co2?
Do you have space for water rez's and a mixing station?
Where is your water supply from?
Going to use reverse osmosis?
Got ph/ppm testers?
Enough fans and air movement in each room?

Lots to think about i wouldnt rush into it...rooms of that size are very costly.

I'm currently at 2nd harvest from 16'x18'x8' room with 10 lights. I don't have an AC, but did ran into heat issue when outdoor temp was above 63 and was able to get it under control with additional intake vent.
The water will be filtered, as for co2 that's a plan, yes have ph/ppm tester. Will have at least 22 wall fans mounted.
Here's a break down of planned new rooms:
-Flower room 20x32x16 (lights hang 12')
-15 de hoods (3x5)
-1000 hps
-12 wall fans
-12" exhaust fan
-12" carbon filter

-Veg room 20x18x16 (lights hang 8')
-9 de hoods (3x3)
-600 mh
-10 wall fans
-12" exhaust fan
-12" carbon filter

-34,600 btu mini split ac x2
-180 pint dehumidifier x2
-100 pint dehumidifier
-16 and 10 light controllers

I'm currently running sun system with solistek ballasts so far no issue as of 2nd harvest. Any recommendation with the new 15 hoods and ballasts i should go with? Run complete system? Titan controllers? Any recommendation or inputs welcome. New Room will be ready in a month, so equipment will need to be ready. Thanks

Theres so many options on lights and ballasts and ive only used a few so i cant give too much feed back on that although theres tons of people on here that could, ive found the digital ones to be crap i use interchangeable 1000watt ballasts that can run on 240 or 120 and can switch from mh and to hps they only cost 110 bucks too. I also run my bulbs vertically in a round white sheet metal hood.

There wont be any RIGHT concrete answer a lot of this stuff is personal opinion other then basics imo anyways lol. I think you are on the right track tons of info in theee forums if you take the time to research.

As far as lights I'be gone to LEC, 315's (6 per 10x10 room). Couldn't be more happy. Also left coco to flow n grows, that like a mix feeling. AC, yea running his lights y'all diffently need ac, I would venture to suggest a split is the way.