GRTI Formation Thermal Conductivity Testing Unit

Know What's Below

Imagine the uncertainty in a geothermal HVAC system designed without essential building details like occupancy schedules, internal gains, and distribution requirements. Why should the loopfield design process be any different?

GRTI's Formation Thermal Conductivity (FTC) testing provides unparalleled insight to the thermal conductivity at your site for your commercial loopfield designs. We designed our industry-leading test methods and cutting-edge FTC test units from independent ASHRAE-funded research, 75-plus combined years of team experience, and over 250,000 hours of testing data.

Unearth Hidden Cost

Your company's system designs, profits, and reputation are too important to rely on estimates. Don’t assume: know your ground properties with GRTI’s FTC testing for your commercial installs today.

  • Incomplete and incorrect data drive up design process time, and introduce error
  • Oversized loopfields add cost with excessive drilling, grout, and pipe
  • Undersized loopfields don’t deliver designed capacity, resulting in increased warranty and service work, uncomfortable customers, and even lawsuits
  • Both scenarios can damage your reputation and the reputation of geothermal heating and cooling as a reliable, cost-effective HVAC solution

Lease Equipment

We ship our cutting-edge equipment to you with UPS (Ground to Next Day Air®). After you test, our professional team analyzes the data and sends a fully-detailed report tailored to your needs.

Lease Equipment


Our certified technicians come to your site, set up, and perform the test. Our professional team analyzes the data and sends a fully-detailed report tailored to your needs.

Need a vertical test bore installed? No problem: we have options to cover that.

GRTI FTC unit side view

Design With


At the end of every FTC test, GRTI provides a professional final report which includes an overview of the method of analysis, thermal conductivity results, and important details about the installation like bore depth, u-bend diameter, grout information, and more.

Ensure Your Project's Success

  • Optimize loopfield designs to the smallest footprint and lowest cost
  • Estimate installation costs with greater accuracy and confidence
  • Drill, grout, and install exactly what the site needs, reducing overall costs
  • Produce more efficient, economical systems that delight your customers
  • Have a reliable, documented record of thermal properties for future reference

Here For You

You know your business, we know FTC testing (also called In-Situ testing, or Thermal Response Testing). Whether you need one test or hundreds, GRTI has you covered. To ensure you have the best testing experience and successful installations, we offer two ways to deploy our decades of experience. Whether lease or hire, we will analyze the testing data and produce a detailed final report that includes calculated thermal properties (conductivity, diffusivity, undisturbed formation temperature), plots of collected data, and drilling logs (obtained from the drilling contractor). A certificate of calibration for the test equipment is also included in the report. You can find example specifications and test reports in our Resources page.

If you need help, our team is just a phone call away. We answer your questions, review conductivity test specifications, and more.

Lease Equipment

We review the details of your request and create a lease agreement to fit your specific needs. We discuss and review test procedures with you to ensure a successful test. Next, we ship the required equipment (FTC test unit, data acquisition unit, and process instructions) to you so you can start testing. After each test, we remotely retrieve the data. Our engineers analyze the test data and then send a detailed report to you.

Rates, fees, and payment terms vary by the duration of your lease and freight costs.

Lease Equipment


We review the details of your request and create a quote specific to your needs. If needed, we assist in sourcing a local contractor to install the test bore. Our certified technicians come to you with all the required equipment for your site. They set up the equipment, perform testing, and send the test data to our engineers. We analyze the test data and then send a detailed report to you.

Rates and fees vary. A signed Purchase Order against the quotation is required before work can be performed.