Building a new modular house in central MD, and have already planned to install a geo system, I have a few reasonable quotes to work from, now it's time to choose between the two that fit the budget.

I have a quote for a water furnance based system, envision series (split 2 zones NDV026 & NDZ026) with hot water assist.  The waterfurnance is a two stager, excellent warranties.

From the same installer, I have a heat controller (comfort aire) single stage setup (split 2 zones HRV & HSS ) models.  I dont think its fair to discuss price because of regional variations, but lets say the comfortarie is ~ 5K cheaper and has less warranty protection.

The base COP comparison is Waterfurnance 4.2 to Comfortaire 3.5.  Say the averages held true, is 5K worth the .7 advantage in COP over say a 10 year time frame?

Waterfurnace software estimates a total annual heating/cooling/hotwater bill of $1400 using their system.

Is comfortaire equipment the Yugo of Geothermal?  Is it penny wise and pound foolish to install one of these systems and not go the best COP/EER's?

Is the extra 5K just piece of mind, or am I getting a significant improvement in cost savings over time.

Joe & Clark, thank you both for the response, it is very much appreciated. Your knowledge exceeds all of the local Geo vets I have spoken with, and its invaluable to have the opinion of a experts with no dog in the fight.

To follow up, the Geo Link Design Studio report said I should average 3.5 COP with the top end Waterfurnace envision series, and an average EER of 18.6 (bewteen the two zones).  The envision is two stage.  I will have a horizontal closed loop.

I don't have comparable figures for the Comfortaire, but my first guess any efficiency delta would be driven mostly by the the lack of a second stage in the Comfortaire system.

That said, since I'm in an area where heating costs will drive a greater percentage of my energy costs,  how necesary if at all is the two stage? 

As an aside, I will tell you, the Geo Link design studio is an amazing software and if I were not stretching my buget already I would chose Waterfurnace in a heart beat.  It was shocking to see what the percentage of my total energy cost is from hot water, it was greater 1/3.  If anything I will make certain to add hot water assist.  Very slick stuff.

Joe, I can't tell if you were saying the comfortaire equipment by heat controller is the same as climate master?  I was wondering why the HRV024 is not energy star rated, which seems odd.