I would start by verifying your units are within spec with respect to power consumptions.  Are you handy enough to obtain current draw measurements for your three units?  Something like:

Unit #1 (X tons), 1st stage: 99.9 amps
Unit #2 (Y tons), 1st stage: 99.9 amps
Unit #3 (Z tons), 1st stage: 99.9 amps

Likewise for 2nd stage.

Your units should have some manufacturer specs that you can check these against.

If these are fine, then I would next look to see if your units are producing the correct cooling capacity, first in 1st stage, then in 2nd stage.  This should be easy to measure on a one time basis, or, easy to continuously monitor with some instrumentation.  If you want to do this yourself, there are many here who can articulate the temperature and power measurements needed along with the calculations.

If these two subjects are fine, then I would next look to see if you have excessive run time.  If so, you can conclude you have structure envelope problems.  And that you really are saving (a lot) of money compared to if you had conventional heat/AC.

I would think the first two subjects I suggest above would be straight forward for an HVAC professional to not only determine, but to demonstrate to you that all is fine with respect to the specific HVAC equipment.  The calculations to determine cooling capacity, for example, on either the air output side, or the refrigerant input side, only require a few temperature and power measurements.

Good luck.

Best regards,

Bill

Without answers to some of the questions above, still, it may be possible to offer a reasonable guess on where the problem is.

If I understand your numbers correctly, you consumed 489 KWH just for HVAC purposes, for a 6 day period.  That's 82 KWH per day, on average.

As a comparison, I have what I and many others believe to be a well functioning GSHP implementation, here in the blistering heat of Dallas.  It's conventional water technology, not DX, so it may not be producing the best of DX-technology performance, but it's probably 'in the ball park.'

I also have an instrumentation system, so I have access to a lot of performance numbers.

For last month, July, I consumed 1174 KWH just for HVAC, which is 38 KWH per day on average.

To rationalize your 82 KWH/day and my 38 KWH/day numbers, we can use the square footage of our residences.  Your residence is 8600 sf - mine is 3400.  Thus, you've got a 9.5 KWH/day/Ksf number, and I've got an 11 KWH/day/Ksf number.

If you assume your basement is not conditioned, and it's about 1400 sf, then your 9.5 KWH/day/Ksf number changes to the same as mine: 11 KWH/day/Ksf.

The next step is one where I don't have enough information to finish - rationalize your 11 KWH/day/Ksf number to your climate.  My 11KWH/day/KSF was for a July climate with many 100°+ days.  I don't know if you have it this hot.

One way to do this rationalization is to use Cooling Degree Days.  For example, for the same measurement period for me (July), I had 644 CDDs, which is 21 CDDs per day.  On a per CDD basis, then, using my 11 KWH/day/Ksf number, it becomes 0.53 KWH/day/Ksf/CDD.

Perhaps you can look up your CDDs for the same 6 day period you measured your KWH.  If so, you can get an average number of CDDs per day for the 6 day period, and similarly rationaize your 11 KWH/day/Ksf number.

Finally, let's say that for some strange reason it was very hot in Michigan, during your 6 day measurement period, such that your CDDs per day average was close to 21.  Then you'd know that your equipment performance is at least to the same as the most current model WF conventional water technology GSHP units.  And thus your problem is most like the residential structure envelope.

But, let's say, as another example, your CDDs per day average is half of what it's here in Texas at the moment (i.e., your statistical average of each day's temperature is about 75 - 76°F).  Now you're looking at about a 1.0 KWH/day/Ksf/CDD number, double my number, which would say something's wrong with your DX equipment, at least as compared to conventional water GSHP technology.

If it were me I'd go off and get the CDD numbers for your area, and do the calculation.  While not an exact, precise calculation, I'll bet it's in the 'ball park' to eliminate either the structural envelope or the DX equipment as your source of problem.

Hope all this helps.

Best regards,

Bill

 To answer your questions, my geothermal units were retrofitted- ie the airhandlers except for the motor -now variable speed are the same.  So, I only have 3 boxes outside-being monitored by the sub meters.  

               My electricity (main meter in July 2009) states our home consumed a total of 2129 kwh although our average HIGH  for the month of July 09 was 75.8 degs F   with temps at night in the 50s and sometimes dipping as low as 47 degs F.  The sub meters were put in on Aug 13th 09 after tremendous pressure on the wholesaler who sold the units to my contractor that I was going to  seek legal advice.   My electricity consumption at the same time  last year(July 08) was 2007 kwh with CONVENTIONAL A/C!  July is typically the warmest month in Michigan.   Also my basement that never requires cooling has 3200 sq ft.  I feel as if I have been taken on a ride.    

I have 11 holes - one hole for each ton.  I am told they are about 50 ft deep(vertical bore) with an umbrella pattern and 10 ft apart in a straight line

        I am going to dig deeper -no pun intended, and persist in getting the system fixed or the energy guzzling equipment removed from my premises.  In the meantime, please feel free to offer dignostics.