A calorie is not a subjective unit. A "clo" is by its definition. >one "clo" equals the thermal insulation required to keep a resting person (for instance, a c

A calorie is not a subjective unit. A "clo" is by its definition. >one "clo" equals the thermal insulation required to keep a resting person (for instance, a couch potato) indefinitely comfortable at a temperature of 21° Celsius (70° Fahrenheit) This assumes we all produce the same output heat. We do not. Even at rest people output different amounts of heat. Normal skin temps range by almost 8 degrees Fahrenheit. Edit: Forgot to add "comfortable" is in the definition and comfort is always a subjective. I might be comfortable in my underwear at 70 degrees. And someone else (apparently) is comfortable in a three piece suit at 70.