Someone has done the work for us.
http://www.leaningpinesoftware.com/h...vacation.shtml
The math and formulas seem correct to me, but other smart folks on here as well, so review and report.
Huge savings indeed
But it should be noted that it does in fact cost less to turn the water heater off when not at home. That will put an end to that arguement by me. Found more information than this, but the site above broke it out into the easiest to read terms.
The last paragraph should also be read for a FYI stand point, just brings another concern to the table.