If i may make a suggestion...
I would NOT try and seal the room/scrub the air inside, that's too hard. Rarely can you seal a room perfectly enough that smell isn't pushed out some crack, smelly air gets out as air in the room is blown around by fans, as well as every time you go in the room and brake the seal. If you really want protection from others smelling your grow, AND to lower your heat, use your carbon filter right and you can accomplish both at the same time.
Remove a small amount of the warmest air in the grow space THROUGH the carbon filter, have no air blowing into the grow space, and don't bother with trying to seal the room, only seal light leaks. This will not only lower your temps like you want, it will create a negative vacuum in the grow space because you're removing a small amount of air through the filter. As long as you have ANY amount of negative vacuum in your grow space, that is where smell WILL stay, it can't get out if the whole time air is being sucked in through all the cracks and crevasses. IMO you're not protected against someone smelling your plants unless you have a neg vac in place 24/7
I run a Can33 carbon filter24/7/365, they last 12-18mo and cost around $100. I under flow its minimum rating so i'm sure it lasts longer and cleans the air even better then expected, and i still change it every 12 mo just to be safe.