Does anybody have experience with both? My wife and I have it narrowed down to one of these, the prices are very competetive with each other.( although I can't seen to get my local Garn dealer out for and official quote and recomendations as to size and install location) I currentl us fuel oil with wood assist (add-a-furnace) I am getting very sick of hauling wood into my basement thru a window, it is also very inefficient (I used approx 9-10 full cord last year)

anyway I hear good things about both of these types of heat and am having trouble deciding and am looking for something to sway me?

 Maybe I can help you out. Let's start with a couple questions.

Well..........maybe more than a couple

What is the cost per KWH in your area and what is your wood going to cost you per full cord.?

If you GSHP will it be closed loop or pump & dump?

Is your current heating system forced air or hot water based?

Where are you located geographically speaking?

The KWH of normal is .0725 and off peek is .0518

Wood is free (cut off of my land)

I am assuming a closed loop

I am located southeast of hastings mn

 So far so good.

Do you have a heat loss calculation for your home?

 Are you planning on heating any other out buildings with the system?

How is your house heated now? Duct system or hot water? Your original post says fuel oil wood furnace but I just want to clarify what you have in place at present. 

No I have not done a heat loss calculation. (I do not know how)

possable a detached garage someday as well as a hot tub

I nopw heat with fuel oil, Duct system

 Don't have a lot of time to get into details right now but here's a couple things to remember when thinking about GSHP based heating.

The biggest impediment I run into when someone considers a GSHP is the existing duct system. The issue is basically one of air flow. A GSHP system, because of limited heat rise available, requires about double the air flow of a conventional heating system. Often times the existing duct system is not adequate to support this increase in air flow.  

The formula for heat transfer with an air based system is simple    CFM x temp rise x 1.08 = btu.   A normal furnace, oil or gas, will work with a temp rise of 45-70*.  A GSHP will only generate a rise of 30-40* max.  As you can see from that and the basic math you need about 2x the air flow to get the same btu output.  

I can't emphasize enough that if you are considering a GSHP you really need to have a heat loss calc in hand so you know precisely what your needs are.

All excellent points mentioned above by contributors. I wish this thread had been present a year ago. It would have put the final nail in the Geothermal heating option coffin for me (although we DID decide on the GARN).

  My $.02 worth..

The complexity of the GARN with its two moving parts (blower motor and door hinge) is orders of magnitude simpler than that of the Geothermal system you are considering.

Another thing to mull over is the life span of the Geothermal system vs that of the GARN. Assuming you perform the recommended yearly water monitoring and treatment, your GARN can last three decades....or more.  And when the GARN blower motor fails it will cost you $259.60 http://stores.garnparts.com/-strse-7/3-fdsh-4-HP-Blower-Motor/Detail.bok to replace it (and I'll bet you could do the removal and install yourself).

I can't imagine the compressor on a Geothermal system lasting 30 years. And when that compressor fails you can be certain it won't be $259.60 for the parts. Furthermore the removal and replacement will not be nearly as simple. At best it will require special equipment to be certain you lose a minimum of the refrigerant which is in those coils which course through the ground outside your home.

Assuming you are correct and the cost of the Geothermal system is identical to that of the GARN, I'll bet at 15 to 20 years you will be either replacing or undergoing a major overhaul of your Geothermal system. Whereas with the GARN you may be replacing the blower motor for the second time at the 15-20 year mark.

You mention you are hauling wood into your basement through a window, and burn 9-10 cords of wood. That is a LOT of wood to toss through an average basement window alright!  With the GARN's 80+% efficiency I'll bet you will cut the wood consumption considerably with the implementation of a GARN, perhaps by 1/3 to 1/2.

Please let us know what you decide.

Hankovitch in SW Wisconsin

 Just talked with a customer who's father built a new house 9 years ago and installed a pump and dump GSHP ducted system. He has very low heating/cooling costs (less than $120 per month in winter) but to date has had over $11,000 in repairs to his system with about $5,000 of it being non warranty.All the manufacturers warranty is now expired and he's thinking of replacing it with a furnace/AC combo.