EcoRenovator - View Single Post - How deep does non-permafrost typically go ?

theoldwizard1 · 03-05-15, 08:52 AM

Well, I sort of, kind of got the information I was looking for (perhaps I did not phrase the question well to begin with).

First, if you Google around you can find charts similar to this one from www.texas-geology.com/

The important data here is that soil temperature stabilizes at about 30'. I have not found a chart that shows deeper reading, but I am fairly certain the do not shift much (although I would still like to see readings down to say 200' if anyone has access to them !)

This chart is from TX, so the center point is pretty high (70F !).

This map from www.hotspotenergy.com shows the average ground water temperature in different parts of the US. I a pretty certain that these numbers line up with the center of the above graph.

So my conclusion is that GSHP are not as big of a "win" for heating and cooling in far northern and southern areas. This surprised me ! I thought below some reasonable depth (20-30') that all ground water (at least water not heated by some geological "feature") was about 50-60F REGARDLESS of what latitude !

Anecdotal evidence is welcome !

03-05-15, 08:52 AM	#12
theoldwizard1 Apprentice EcoRenovator Join Date: Oct 2014 Location: SE MI Posts: 105 Thanks: 3 Thanked 12 Times in 9 Posts	Well, I sort of, kind of got the information I was looking for (perhaps I did not phrase the question well to begin with). First, if you Google around you can find charts similar to this one from www.texas-geology.com/ The important data here is that soil temperature stabilizes at about 30'. I have not found a chart that shows deeper reading, but I am fairly certain the do not shift much (although I would still like to see readings down to say 200' if anyone has access to them !) This chart is from TX, so the center point is pretty high (70F !). This map from www.hotspotenergy.com shows the average ground water temperature in different parts of the US. I a pretty certain that these numbers line up with the center of the above graph. So my conclusion is that GSHP are not as big of a "win" for heating and cooling in far northern and southern areas. This surprised me ! I thought below some reasonable depth (20-30') that all ground water (at least water not heated by some geological "feature") was about 50-60F REGARDLESS of what latitude ! Anecdotal evidence is welcome !