Boil off rates

[user 103393]

I posted my first recipe and someone commented on my boil-off rate and how high it seemed. With my pot 7.5 stainless steel gallon pot roughly 12" wide, I can boil off 1.5-2 gallons/hour depending on temperature and wind. That's on a 38000 BTU propane burner.

Is this 'abnormal'? I don't live anywhere too strange - well, I mean it is New Jersey - but nothing like arctic temperatures or monsoon winds.

 

[Musky01]

Doesn't seem outrageously high, my pot is close to the same dimension and I boil off between 1.25 and 1.5 gal/hour