Geothermal bore length

[contrades]

I'm starting a Geo system for a log home in about two weeks. Heat loss/gain calls for 4 tons; geo design software dictates 755 ft of bore length (vertical wells) in silt/clay. 755 ft seems excessive but geo design calls for this. Is there something I may have overlooked? Thoughts? Also how much of the horizontal run (in feet) can I count towards the required bore length?

Thanks, C

[sctronics]

We bore 150' per ton. 4 bore holes = 4 ton 150' each hole. If we hit rock say at 75' you would drill two holes for a total of 150'.

Steve

[progressive]

The 755 ft is divided by 4. Make the holes even say 4 175 ft. Run them in parrallel. The grout used for the holes could change the depth. You would need to do the figuring for a horizonal loop. the distance to the manifold is normally not used in the calulation of the loop. It is better to be longer than shorter in the disign of the loop. I would highly reccommend if you are not, use a IGSHPA credited installer for the loop install.