Those results are typical for my area as well, propane costs can reach near three dollars a gallon, oil is more then that. A recent install was done last october on a home with propane and a/c, he has now saved almost 2800.00 to date. Less then six months, on a 3000 sq ft home. I have dozens and dozens of jobs like this one. However I have only done one vertical loop. They just cost too much around here, at 15.00 a foot or more here, unless its a commercial job with lots of bores, it is very exspensive to do a vertical loop!