To search for a qualified installer check the IGSHPA link below. Don't expect these installers to know anything about DX. You will likely receive the best information from an installer that has experience installing both systems, a somewhat rare breed indeed.

Any geothermal system properly designed and installed should work fine, DX or conventional (liquid-to-air, liquid-to-water).

Each type of system will have their pros & cons. For residential applications I liken the difference between conventional and DX geothermal to PC verses Apple with DX being the Apple version.

Personally, as an accredited geothermal installer, designer and consultant it is my own biased opinion that the only DX system I would install without reservation is the Nordic DX system. The complete line of Nordic heat pumps is excellent in my opinion. No other geothermal manufacturer offers as wide an array of equipment as Nordic. We have such a system (Nordic DX-45) in our own home for almost 8-years now and will be in our 9th heating season starting this fall without any breakdowns or service being required. If you chose DX you need to know that your ground is ph neutral so that the copper ground loops will not corrode.

You may consider a split geothermal unit with a Carrier Infinity fan coil unit and Infinity thermostat if you go the forced air route. This may be easier to install in some cases and provide enhanced control. Don't over look the triple function units if forced air and full capacity hot water are required in addition to DHW.

Since you do not have any ductwork you may also consider a DX-to-water or conventional liquid-to-water heat pump with either in-floor radiant and fan coil units or just fan coil units. This way you would not have to install ductwork at all and would only need about 2-inch diameter floor and wall penetrations to run insulated pipes to the fan coils and condensate pipes to a drain. You could have central heating and air-conditioning with each fan coil unit being a separate zone as they can be controlled separately. This is a very energy efficient configuration, however, it will not be inexpensive!

For fan coil units see these links:

http://www.multiaqua.com/pdf09/Multiaqua09_CFFWA.pdf

http://www.multiaqua.com/pdf09/Multiaqua09_MHWW.pdf

Note that these are very low temperature hydronic units, a perfect match with geothermal, entering liquid temperatures as low as 100 degrees F.

Here's the link to Nordic:

http://www.nordicghp.com/nordic-products/product-overview.html

SR

Here is a link that might be useful: IGSHPA

Make sure your geothermal installer has done ground loops before and that they are IGSHPA certified as listed above. Ask for referrals of existing customers. You can also look at companies like WaterFurnace or Carrier etc. and most of them have dealer locator maps on their website.

Ask what factory training the company has received, some states like my state of Oregon also certify the companies.

Thanks for your responses.

I have almost given up on the idea of installing a geothermal system. Only 1 company has come back with an estimate (I met with about 6 or 7 for estimates) and I started the process in the beginning of July.

I'm not sure why no other company followed up with an estimate but this process has been draining to say the least. I am now very weary of the installers in my area and really not confident any of the people I met with has a clue when it comes to geothermals. So, though ideally I'd like to pursue geothermals as an option, it really doesn't seem like for me.

Thanks again for your input.

That being the case, I would recommend looking into the Carrier Infinity Greenspeed series (25VNA) of conventional forced air heat pumps. They are currently the most energy efficient air-source heat pumps available.

SR

Where are you building the house climate has a lot to do with the proper system for the house.