Geo Thermal install costs?

[crabjoe]

My propane bills, to heat my home in the winter, have been so high, I'm thinking about converting to Geo Thermal setup as my primary AC/Heat source and using my Propane heat as the emergency backup. The dang budget plan is almost $200/month and I don't even get filled up for 6 month!

From my understanding, the installation is pretty straight forward and most of the cost is in digging. So now I'm thinking about costs...

Assuming I can dig a trench, can someone tell me how deep and long it would need to be? Does one need say 100 ft long for ever 100sq of home? Can I snake the trench so it's a foot apart or does it have to be 2 or 3 feet apart?

I'm trying to figure out how much of my yard has to be torn up since I can't afford to have a well drilled. Also can one purchase the parts for a Geo thermal setup to do it as a DIY project? Is there a break down of costs I might be able to find somewhere?

Thanks!

[mrcaptainbob]

geotherm...

A friend recently checked into that. His place is about 1200 sq. ft. and it was estimated he'd need about 4,000 feet of 1" tubing in the ground. It would be at least 4' deep and spaced at least 4' apart. Since he has acres of fields around him, he could easier just do a loop. He's still considering going the route of drilling the well(s) as it could be cheaper. Unless he does the trenching himself. There is a formula for figuring it. How big the house is and it's composition ='s how many tons of heating is required. This then translates to how long the ground tube needs to be. A moist area is best as it conducts the heat better. The best thing about geo is that you get the a/c benefits free. It just works in reverse for the hot days!

[crabjoe]

4000ft?? That can't be right. I say that because I just find that hard to believe. Although not as efficient as a Geothermal heat pump, a regular condenser doesn't have anywhere near that much tubing.

If anything I thought a few hundred feet of trenching would do, since the tubing is coiled in the trenches.

BTW, what makes Geothermal so complicated? From the way I see it, it should be as easy as replacing the outside condenser's coil with tubing that runs underground and leaving the same evap setup in house.

I see this... Tubing underground or in water, a box (Similar to a condenser) that pumps whatever (Water, rad fluid, etc) though the tubing to exchange the heat and to carry it to a evaporator at the ducts. Why, why isn't it that simple?

[HayZee518]

geo thermal temperatures range from 54 to 57 6 feet down in the ground. a closed system of ethylene glycol is pumped through the system to absorb ground heat or discharge heat to/from the ground. the glycol goes through another heat exchanger to pick up/discharge heat from a closed loop freon system. next the air is blown into the dwelling. if the temperature is below nominal an auxillary heater is started up ahead of the heat exchanger for heat and uses machine fan to blow the heat into the house. for costs you have to consider amount of heat/air exchanges per hour for a given temperature variation say 68-72 degrees. what you can absorb from the ground in a 24 hr period. electricity used for the glycol pump, compressor, air handling. next is cost of freon and which type R-12, R-22 or R-134a.