So what we've been putting in homes for ~40 years already. Thanks Google!
My parents almost bought their "retirement home" with an existing geothermal system - it remains the only "real world" home instance of this technology that I have encountered.
$20K also seems very close to the price he told me years ago - I fail to see the innovation here. I'm sure there's something here, but the article doesn't help illuminate it.
Edit: Another HNer posted this, apparently it's a cheaper drilling technique: https://blog.x.company/introducing-dandelion-2706eded169a
I.e. if you install solar by itself, you save X dollars/month. If you install this by itself, you save Y dollars a month. If you install both, is it close to X+Y, or is there some substitution there?
On one hand, you can sell solar back to the grid, but you can't always sell it back at retail, so I would guess your savings would be smaller, but how much smaller? Or would you be able to achieve the same ROI with a smaller rooftop solar installation?
TBH, I'm not really a big fan of rooftop solar, it seems like a hack to deal with shitty environmental policy that undermines the electricity grid itself.
If you live in a climate where you need to heat in the winter and cool in the summer, ground source heat pump are cheaper to operate than oil, gas and A/C. Solar will contribute to reducing your A/C electricity bills and also all the other power you use year-long, so they work together.
If you live in a climate where you occasionally turn on an electric heater for those really cold days, this will only help during cooling season, while solar will contribute all year long.
This is compared to air heat pumps, where they give you a single number with no factors, and your system rarely will get that number given your set of variables. You can get the full performance sheets if you nag the crap out of them or you are a contractor and have access to the service site.
It is significantly more common in areas on the east coast (which has a good climate for it) and also areas where wells need to be drilled anyway.
It's less common in areas with city water/sewer.
When i talked with the well drillers, they were doing a bunch of residential geothermal installs each week, so ...