The borefield is half the cost of a geothermal system. Half. The other half — the building mechanical, the heat pumps, the distribution piping — comes with ASHRAE performance standards, manufacturer warranties, commissioning procedures, and a rich set of specifications that have been refined for decades. If a chiller underperforms, you measure it, you prove it, you file a warranty claim or you get it fixed. The contractual machinery exists. It works.
Now look at the borefield. No trajectory requirements. No drilling specifications beyond "drill a hole." No construction quality metrics. No warrants against thermal interference between bores. No mechanism to measure plan against actual. No way to verify — even modestly — that the asset you paid for will deliver the thermo-economic outcomes you were promised.
It's turnkey. Which is a polite way of saying: you get what you get.
The Asymmetry
You wouldn't buy a car if the transmission came with a warranty but the engine didn't. You wouldn't sign off on a building where the mechanical plant was specified to four decimal places but the foundation was "contractor's discretion." Yet that is exactly how borefields are procured. The most expensive, most permanent, least recoverable component of the system is the one with the fewest enforceable quality standards.
This is not a gap. It's a void.
The Overdesign Tax
Any engineer worth their salt knows how to avoid being responsible for a failure: overdesign. Add more bores. Go deeper. Increase the spacing. Build in so much margin that even the worst construction quality still limps past the performance threshold. It works. Nobody fails. Nobody gets blamed or held accountable.
But overdesign is waste. And it's the worst kind — the preventable kind you can't even measure. The kind that doesn't show up as a line item anyone questions, because the borefield "works" and there's no baseline to compare it against. The kind that quietly steals dollars from other projects. That sinks capital into the ground that can never be recovered.
You can't resell a geothermal bore. You can't repurpose it. You can't move it to another site. If that bore wasn't needed — if it exists because the design carried 30% margin to cover for unmeasured construction quality — then the money spent drilling it, grouting it, and connecting it is gone. Permanently. It is absolute waste.
And it compounds. Overdesigned borefields drive up the capital cost of geothermal. Higher capital cost makes geothermal less competitive against conventional HVAC. Less competitive means fewer projects get built. Fewer projects mean less market learning, less contractor specialization, less downward pressure on costs. The waste doesn't just penalize one project — it slows the entire industry.
What Comes Next
This is the problem I've spent 15 years watching from drill sites, design offices, and bid tables. Not the absence of good engineers — there are plenty. Not the absence of capable contractors — they exist. The absence of a common, enforceable framework that connects construction quality to thermal performance and gives every party in the chain — owner, engineer, and contractor — a shared basis for defining, measuring, and warranting what "good" looks like.
Over the next series of posts, I'm going to lay out the case for a physics-driven, probabilistic set of methods to systematically identify and root out this waste. Methods that replace margin-of-ignorance with margin-of-confidence. That give owners something they've never had: a measurable basis for borefield acceptance. And that give good contractors something they've never had: a way to prove their work is better.