alt Hacker NewsTo jakozaur’s point, there’s plenty of reasons drilling can get cheaper and there’s at least one other company working on it [1]—would love to hear about others! I’m a minimally informed amateur but my intuition is that the way it’s typically done (multiple inch borehole, U-tube geometry) is fairly suboptimal since the diameter is a lot wider than you need it to be just for hydrodynamic resistance and you get losses from the outgoing liquid cooling the incoming liquid. Dropping the diameter should make drilling a lot easier—-you can sink a 5/8”x12’ ground rod with hand tools in the right soil! (you’d still have to figure out how to make the holes meet up but I imagine there are ways of doing this).
The fact that you need to roll out a drilling rig plus crew at all is going to be a large part of that cost. For it to become interesting for the average homeowner the price is probably going to have to drop by something like 75% - but that basically kills any margins for clever new innovations...