Nope you are fine, exchanging the air in a room even once a day is ok and will not harm the plants. There are many who use A/C and they never change out the air. You do need to keep a fan moving the air out from the underside of your leaf's to push out the old air and bring in fresh air for the stomata. Moving it above the canopy will mix in the old air with the new oxygen that the plant is producing so you air does not get toxic or anytihng like that to worry about.

Your temperature range is fine and I would not worry but keep an eye on them just the same.

Happy growing