PFF - geo is very popular in Texas and very efficient. Geo will cool your home in Texas using a lot less electricity than a typical air-source unit. If Bruce ever sends you 12" Bluegill I want some too.
The up front costs to install geo are higher. The systems we put in are usually 3-5 tons for homes 1500-3000SF. Usually about $15K to $25K total for HVAC system installation but there are a lot of variables. - we sometimes do zoning, air cleaning, swimming pool heat, radiant floors, etc.
Air source heat pumps are very competitive with other choices ( I prefer them over gas and oil and I own one - yes they work great north of the mason-dixon line). A geothermal system costs probably about $5,000 to $10,000 more than air source (or gas or oil). If you are building with a 30 year mortgage the upgrade will cost you maybe $40 per month on your loan payment. It will save maybe $60-70 per month on utilities. Black ink from day one. You can make this analysis as complicated as you want. Black ink from day one is a reality.
If you are considering retrofitting with geo we charge more for that - it just take more work. A geo retrofit for a 2500 SF house might cost $15-20K. Often the electric service needs upgraded to 200 amps at additional cost ($2K).
I have found people get all hung up on the upfront cost and can't see the operating cost pays for it.
If you pay $500 for a refrigerator and a more efficient model is $800, and the lower cost model uses $1500 more electricity over its lifetime (about 20 years) which one is cheaper?
PFF - you can find out what the average ground temp is at 5' depth by asking your local HVAC contractor. You will have to ask someone else about drilling a well - my experience is with closed loops - no well required. If you are serious you need to find a local HVAC contractor with experience in geo. One way is to go to waterfurnace.com and select "dealer locator" or something like that.
