This is so random but I've confused myself. I have 2.5 tog sleep bag that I want to start using on my baby, it states using a cotton body suit if the temperature is 17-20 degrees, does this mean outside temperature or room temperature? And also do people put just a vest on and no sleep suit/baby grow? I don't want to over heat my baby, he is 4 weeks old but hates being swaddled. Thanks for any info