Hey guys, I've visiting this site for a while now learning all about ground source heat pumps and would really like to use one on our new home we are building. I've had a manual J and D completed, and now the ground loop design in coming back and I just don't understand how these folks are coming up with their numbers. Here are the details:

House size: ~5170 sqft. (I know this really doesn't matter, but thought you would like to know)
Location: Mountain area just East of Albuquerque NM (Very similar to Santa Fe, NM)
Elevation: 6890'
Ground temp: 66-68 (according to all the charts that I have seen)
Ground material: Limestone (we had a soils report done)
Heat loss: 90,510 Btu/h

Loop design will be vertical, we have 2 acres, but there is limestone just under the surface and trenching would be difficult.

Some folks (I don't know who came up with these numbers exactly) believe we need the following:

Bore holes: 9
Depth: 300'
Pipe size: not listed

What do you guys think? I know some of you have access to the computer software that can size these loops, would you care to run my numbers? I think that the size should be more like 8 bore holes at 250' each, and that may be over doing it still.

Please help, over sizing this loop will put this system out of reach financially!!