Geothermal Site Assessments are live in the DrillerDB console today. Enter any US address or coordinate pair and you get a ground thermal conductivity estimate with an explicit uncertainty range, plus heat capacity, thermal diffusivity, undisturbed ground temperature, aquifer flow and static water statistics, and the full subsurface profile the numbers were derived from - packaged as a professional PDF report. One click seeds a ground-loop design sized by GHEDesigner. Formation thermal-conductivity tests you run in the field can be logged back into DrillerDB, where they anchor future estimates near your own sites. It ships as a $149/month add-on on any DrillerDB plan, included in the 14-day free trial.
Why we built it
The industry's own design tools ask you to bring a drill log and average it by hand. DrillerDB brings the drill logs - 18 million of them.
That is the whole idea. Ground-loop sizing turns on a conductivity number, and on most projects that number is either a measured thermal-response test or an assumption. The design software professionals already use expects you to arrive with a borehole log and work out a thickness-weighted average by hand. DrillerDB has spent years assembling driller-reported well records from state databases, so on most US addresses the logs are already there before anyone drives to the site.
Before building it, we went looking for the same tool somewhere else. We could not find another nationwide, address-level ground thermal conductivity estimator anywhere in the published prior art. National screening tools fall back on climate-zone defaults for the subsurface. Address-level tools exist only city by city. Geology-derived conductivity maps top out at 1:250,000 scale - and mostly outside the US.
How well does it work
We blind back-tested the engine against 21 publicly logged thermal-response tests across 13 states, spanning humid, arid, and mountain regimes. The measured conductivity fell inside the report's stated range at 18 of 21 sites (86%), with near-neutral average bias (-3.9%). Ranges are site-specific - wider where well coverage is sparse - and every report carries a confidence grade.
This is not a replacement for an on-site thermal-response test. It tells you whether a site is worth testing, and gives designers a defensible starting number where no test will ever be run. A formation TC test runs $8,000-$12,000 per borehole and takes a week or more from spudding to a number; run it on the sites that deserve it.
Why the number carries so much weight
Drilling and the loop field account for 50 to 70 percent of total ground-source heat pump project cost. A conductivity error therefore does not nudge a rounding line - it mis-sizes the majority cost driver, either by adding boreholes nobody needed or by under-sizing a field that will underperform for its entire service life. The measurement that settles the question is priced out of exactly the projects where that risk lands hardest.
The demand side is not small. A 2023 analysis from DOE, NREL, and ORNL found that retrofitting roughly 70% of US buildings with geothermal heat pumps could cut national electricity demand by up to 13% by 2050. With the residential 25D credit ended for installs completing after 2025, cost-sensitive commercial projects - where the ITC still applies - are exactly where a low-cost upfront screen has the most leverage.
How it works
- Enter any address or coordinates. The engine finds nearby logged wells, builds a consensus lithology column, and splits it at the local water table.
- Each layer gets published literature conductivity and heat-capacity values (VDI 4640, Banks, Fuchs & Forster), thickness-weighted into effective properties - deterministic, reproducible, never AI-guessed numbers.
- You get a professional PDF report with an uncertainty range and confidence grade - and one click seeds a ground-loop design sized by GHEDesigner, the open-source sizing engine from the same Oklahoma State University research group behind GLHEPRO.
Available now
Geothermal Site Assessments are available to every DrillerDB customer today as a $149/month add-on, and they are part of the 14-day free trial. The geothermal site assessment page has the full picture, including what lands in each report and what the add-on covers. If you already run formation TC tests, log them in DrillerDB - measured results anchor the estimates near your own sites, so the tool sharpens exactly where you work most.