Could someone please recommend the highest quality geothermal HVAC system for small affordable homes in the 1000-2000 sq. ft. range, single story, and sip built.  These homes will be built in Texas.  Thank you in advance for your comments.

I'm confident many here will contend that all geothermal HVAC brands will work exceptionally well, as well as all technologies, as long as there's an excellent, very high quality installation.

Living in Texas (Dallas), my experience with WaterFurnace equipment has been exceptional.  I have the 3 and 5 ton 2-stage variable speed Envision water-to-air GSHP models, connected to a closed vertical loop.  Many performance details are available at http://welserver.com/WEL0043 .  I have the instrumentation sophistication to affirm my units are performing to WF's advertised claims.

WF's smallest 2-stage variable speed Envision water-to-air GSHP unit is 2 tons.  It's ARI/ISO 13256-1 Performance Ratings, for 1st stage, are 23.8 KBTU/h at 34.5 EER (cooling - 59° EWT) and 19.8 KBTU/h at 5.7 COP (heating - 50° EWT).

I can also recommend an HVAC firm that specializes in WF equipment installation and is large enough to handle multiple homes.  Contact me for details if desired.

Hope this helps.

Best regards,

Bill

Devon,
If you do go geo, follow local referrals. Contractor support trumps brand most times.
I'm more curious about why we'd look at geo for a 1,000 SF, SIP house. In a cooling dominated climate, I would expect an air source heat pump to be more attractive when comparing cost vs benefit. Get a pro to do operating cost comparisons for you.
J