1 watt = 1 joule/second. 1 calorie = 1 gram of water changing temperature by 1deg C. 1 gram of water is 1 cubic centimeter. There are 3785.41178 cubic centimeters per gallon, and deg F = 9/5 * deg C + 32. 1 calorie is 4.184 joule
Now, 60 deg F = 1.33 deg c and 170 deg F = 62.44 deg c, so 61.11...