When taking a bath, we use approximately 450 lbs of water. How much heat, measured in British Thermal Units (BTU) is required to heat the water from 60 degrees Fahrenheit to 104 degrees Fahrenheit?
I do not know the specific heat of water in obsolete units of BTU/(pound deg F). You do, use it in
BTU heat input = Specific heat of water * 450 pounds * (104-60) degrees