ok im gonna grow in my attic but the temp is anywhere from 60(night) to 80(day) and the humidity is very low at about 27% pretty much the whole time. i dont know how my 400w HPS/MH light will add to that tho. theres one window so im thinking if i put in an air conditioner in that window and put my box( 26"x17.5"x69") right in front of it it will cool it down and give some air flow to my plants. will a humidifier be enough to get the hum up to 50-60 where it needs to be. what should i do?