Can anyone suggest some Geothermal heat brands or installers for the Duluth, MN area?

From the calls I've made some seem reputable, and others seem to be a one- man operation.
I'd like to hear from anyone who has a Geo system in-place, what brand you used, and who installed it.

Thank you.

Also, I've had one contractor tell me they'd fill the ground loop w/ a windshield washer solution to save on cost vs. anti-freeze. Is this a common practice?

That is NOT standard practice. I doubt IGSHPA approves of windshield washer solution in a ground loop. I would also check with the state of Mn to get their thoughts...

Bergy

I'm not saying it's a good practice for a pro, but if you look up the MSDS sheets for the cheap blue stuff, it's just Methanol and water. I believe a lot of fleet operations buy Methanol by the drum and mix their own washer fluid.

I have seen a lot of that used around my area. As stated it's just Methanol.

My latest issue w/ these contractors is the manifold of the system. One is proposing a heat fused in-ground manifold with a lifetime warranty, another wants to construct the manifold in my mechanical room (Using mechanical fasteners.)

Is there an advantage to either system?

I'd like to have room in my utility room for off-peak water heating, but the inside manifold may be too large for it. Having said that, the in-ground manifold will give me back some space but what happens if there is leak?

Thx.

There are many "one" mane operations in the heating biz in general. They out number large shops hands down. Do not over look them as inferior. Go with installer with best references. The best brand is the one they use.
Re manifold a heat fusion manifold that passes pressure test will hold water for your lifetime, the same is not necessarily true of mechanical joints. I'll bet your mechanical loop guy isn't IGSHPA certified; you should check his references more closely (it leads me to wonder about his time in the geo biz, though exceptions do exist).
Joe