always keep the exhaust running no matter what, you'd e surprised how quickly bud rot sets in even a short break will increase your chances of getting damaging bud rot in there. good news is the exhaust will help with temperature. for increasing the humidity, you can get a humidifier, or even an evaporation cooler if you want to also keep the temperature down. these can be quite cheap also. So short answer : never turn off the exhaust, and get some cool mist . your plants will surely love it ! Hope this helps ! š