Sizing and Installation become even more important on Geothermal. It adds a water side component similar somewhat to a boiler. Whereas a air source heat pump uses a fan on the condenser, which is preconfigured from the mfg., a geothermal needs a properly install ground loop, with adequate capacity (lenght of loops & proper backfill), then the circulation pumps much be sized and installed correctly. North Dakota is a fairly balanced climate, it's both very hot mid summer and very cold in winter (actually one of the most extreme climates in the US, next to parts of Alaska), so you'll have less of a compromise than you might for example have in Michigan, Canda, etc. where summers are more mild.