I've discovered an abandoned water well on newly acquired land in south central New Mexico. Hearsay is that it was drilled 4 or 5 years ago and was abandoned because of insufficient water production. The 7-in-diameter borehole does not have a casing, and goes down 720 feet. Water starts 230 feet down. Overburden is minimal/shallow. What's the best way to tap this great resource for heating and cooling a new house near the borehole? Open loop, closed loop, one closed loop, two closed loops, etc.? What's the easiest, quickest, but accurate way to determine the capability of this resource? rules of thumb like 1 ton per 200 vertical feet? or field testing? What are the costs? I will need to compare the costs of additional boreholes vs. reducing the building loads by changing the design to include more insulation, better windows, air sealing, passive solar, etc. How close must the rating of the well match the building heating and cooling loads? If an additional borehole is needed must it be the same depth? or can I drill it shallower, say to 400 feet, and balance the flows with a header approach? Can I avoid the cost of drilling additional boreholes by going to a dual-source (ground and air) system? Who makes such units? Who can do the analysis, and who can do the work for me in the Truth or Consequences to Las Cruces area of south central New Mexico? Thanks.