Jeff, I'm looking too and I live in Niantic. I'm building a workshop and thinking of a post and beam building on a radiant concrete slab with a sips envelope. I'm trying to find someone in the area who has worked with sips and post and beam as well as a geothermal firm. We might put in one closed loop field and see if there is a way to heat both our house and the workshop. The house is about 24 by 36 and is an old barn itself; heatload and cooling load between the two buildings will be very different.

1.  I think so.  The I would estimate the 'incremental' cost of geothermal over a gas heat / AC combo as being around $10k.  The difference in utilities is probably around $100 per month.  That is a 7 year plus payback, but consider the other benefits:
 - First, the synergy 3 geo pump has been making our hot water unaided by any other heat source - and we've been happy with the output.  This probably saves $200 to $300 per year. 
 - Second, the synergy 3 supports the radiant heat (through the potable hot water tank) w/o a boiler, saving at least $1000 in equipment and allowing us to run clean water through the tubes (better in the event of a puncture).
- Third, we have a single piece of hardware housed in the basement - it should last 20+ years.  This is much longer that the service life of a furnace with a heat exchanger bather in combustion gas or an AC compressor.
 - Third, we don't have a noisy AC compressor in the back yard to ruin a quiet summer evening.
 - Fourth, we have no carbon monoxide risk.
 - Fifth, if we wanted a backup generator (and we don't), a smaller generator unit could heat and cool the house indefinitely.

2. I think the question about a qualified contractor was addressed.

Jim

Jim,

Your numbers seem pretty reasonable, but I'd add about $6k to make sure you have enough to get the pipe in the ground.   Also, in my analyses of very low energy homes for sunny, cold, dry cllimates, I can't justify that extra $16k.  Instead of averaging $100/mo. savings, I'm only spending $70/mo. to heat the house for 4 months.  If geothermal took that down to $30/month, then I don't think the geo equipment has paid for itself before it needs replacing.

We have the real advantage here of not really needing compression cycle A/C.  Most consumers still believe they need it, but a unit like Coolerado can do the job with evaporation cycle cooling even on the hottest days.  So I wouldn't have any summer savings, except for the domestic hot water.

The $10k included the wells.
The wells were about $4500, and the pump was about $7k.  A 90% furnace & AC is atleast $2500, so the geo system is about $10k more. 

Also, the total HVAC bill was $42k, which included wells, pump, ducting, warmboard, radiant system w/manifolds.  Going with a furnace & AC would have saved about 25%.
Evaporative cooling works  great - in colorado.  I've stayed at a friends house in Denver with a swamp cooler, and it was very comfortable.  As you know, they don't work where it's persistently humid.  Welcome to Ohio.

If you do live in a climate where you need compression cycle AC and a furnace, I think the value of the geo system comes out in several ways beyond just a lower monthly bill - for example, longer equipment life, combustion-free environment, reduced noise and heat exhaust.

I'm convinced.  Now the production builders and semi-custom builders need to be convinced.  I think that consumer demand is what convinces those builders.  Unfortunately, the topic is a little too complicated for the average consumer to get a handle on.