okay, so here are the results of my heating pad testing with no other heat source. I put the heating pad on at 5:02 and was going to go for a straight hour and then test temp but my husband wanted to go to happy hour and threw things off. So, I took the temp at 5:34 and it hadn't even hit 90 degrees, the heat pack was still cold. was wondering what was going on with the heat pack by this point. i decided to go out and leave the heat pack rubber banded to the QF and was gone around an hour. when i got home i checked the temp on the QF and found it to be 92.7. This was just with the heating pad attached and it sitting in a drawer. I took the QF and crotched it for 30 minutes and measured the temp and it was 97.9. I am sure if I had not removed it, it would have hit that temp sooner. My thoughts are that even w/o a microwave/hot water/etc. you may be able to reach the right temp within 2 hours. Obviously, I will practice this again. The hand warmers I used were heat factory brand and say they last ten hours? hope this helps and if anyone else has any suggestions for me, please let me know.