Here in SE Alberta it costs $9-$15 per foot :(

I just got another quote the other day. $2700 to drill three (3) 200' deep 4" diameter wells. So, less than $5/ft. This is in red clay/shale. This is in central Arkansas.

Wow, that's cheap.

In Texas we're averaging $4.00 to $4.20 per foot on water sourced geo (drilled, loops and grout).  DX geo is $3.75 per foot without grout or copper.  A guy southwest of the DFW area got his drilled for $2.50 per foot.  I'm not convinced though the driller has his driller's license number on the fender.

Wow, in Texas it should be: "Geothermal Drilling. We're Dirt Cheap!"

Hi Accurate1

I too live in RI and have been looking at geo since last summer. I see you are a driller and was wondering who you use for the inside HVAC portion of the job, or do you handle the whole thing yourself? Do you use the Earthlink system?

Thanks

Just curious, on the these prices what grout is getting installed? Are the plastic loops being installed with standard bentonite grout or thermal enhanced grout with silica sand? Texas prices are dirt cheap.
Thanks

In Texas, the water sourced is being grouted with bentonite and the DX price does not include grout.  Typically, it is thermally enhanced but we are probably going to push the supergrout from this point forward.  The reports we are getting back is that it improves the efficiency of the DX by 20%.

We are a drilling company in east central Ohio and have been installing geo loops since 1990. The main factor in drilling costs is the formation that the driller must deal with. In Ohio this can vary widely, we as a subcontractor to the HVAC dealers have always tried to give our clients a set price that they can use in their quote process. Over the course of our experience we have a good idea of what to expect when a project is sent to us. I guess what I am trying to say is every area of the country will have different things that will affect drilling costs, formation, contractor availability, competition, and local regulations just to name a few.

ps: Our average cost for an existing home is around $1750 per ton (150' bore/ton), includes all piping standard bentonite grout, complete hookup,flush and fill but without the flow center

Can anyone tell me why the loop length for a vertical loop is so much shorter than a horizontal loop for the same tonnage.

One reason is that earth temp below approx 30' depth is not affected by surface temperature so is a better source / sink for geo heat transfer.

Is that the only reason?

It may also be that the high cost of drilling vertical leads to acceptance of design for higher EWT for vertical vs horizontal - balance of first cost vs operating cost.

It seems like there is a substantial difference between the average vertical depth discussed here (about 150' down and 150' back) and the average horizontal (600-1000'). That's a pretty significant difference. Is the ground temp., below 30 feet, about the same everywhere regardless of climate?

Deep ground temp will generally be the same as the yearly average air temp. In other words very different in Florida and Minnesota for example.

The exception is if you're in an area with real geothermal energy.

If this is true then that brings me back to my original question.  Why are vertical loops so much shorter than horizontal loops for the same tonnage?

My well cost $12K 10 years ago 612 ft in some painful ledge. Yikes.

My guess on the vertical loops is that they have to have more 'contact' with the earth because at 6' the temp is not as cool. It would use the energy of the movement of fluid as much as picking up energy from going down then up. It's a total guess, but I'm sure someone here really knows the answer.

The ground temp a 5' depth can be as much as 10° colder than the deep earth temp.

This is why the horizontal loops need to be so much longer,  they are drawing heat from colder ground.

Thanks for that chart Dewayne. Interesting info.

It's surprising though, that such a "relatively" small seasonal fluctuation in the surface ground temp would neccessitate an increase of about 100% (or more) in the horizontal loop size vs a vertical loop size. Seems counterintuitive - but what do I know.

Dewayne, that is an interesting chart. You really are a great rescource.

Please bear with me, I have a question, would the fluctuations be different if the soil was different? For example, my rocky soil must hold heat differently than clay or sand. Wouldn't it fluctuate more if the ground were wetter or drier? Or if the climate of a particular area was more varied? I find this stuff really facinating.

Mary