A transparent, side-by-side comparison of two geothermal installation methods — with every tax credit, demand charge, and long-term energy saving built right in.
This interactive tool was built for building owners, contractors, and developers who want a clear, honest answer to one question: Which geothermal installation method actually saves more money — and by how much?
ThermoVault is a trench-based, water-to-water heat pump system that stores thermal energy in the ground beneath your building slab. It heats, cools, and dramatically reduces your utility bills — including demand charges that most systems completely ignore.
The calculator compares ThermoVault's trench-based approach against the traditional borehole geothermal method, accounting for gross installation costs, federal tax credits (Section 48E ITC), bonus expensing under the One Big Beautiful Budget Act (OBBBA 2025), annual energy savings, and a full 30-year projection. Every number is adjustable so you can plug in your own real-world figures.
Deep vertical holes are drilled into the earth — typically 150 to 400 feet per bore — and filled with grout to transfer heat. It works, but drilling is expensive, disruptive, and produces no additional tax credit benefit beyond the base ITC rate. The drilling cost itself does not qualify for the Investment Tax Credit.
Horizontal trenches are excavated beneath the building slab. The excavation, thermal fill, PEX tubing, and underground insulation are costs that would exist in any construction project — but with ThermoVault, those same costs now qualify for the federal Investment Tax Credit. That's how the system pays for itself.
Here's the key insight most people miss: excavation, CLSM thermal fill, PEX tubing, and underground insulation are costs that belong to every major construction project. Whether you're pouring a radiant floor, running utilities, or doing site prep — those line items exist in your budget already.
With a borehole system, you still pay for that site work — and then you also pay an additional $90,000+ for drilling. That drilling cost does not earn a federal tax credit. You're spending more money for a benefit that doesn't qualify.
ThermoVault flips the equation: instead of adding drilling costs on top of your existing construction budget, it channels your existing excavation and infrastructure spend into a system that qualifies for the federal Investment Tax Credit (Section 48E). The result is a lower gross cost, higher tax credits, and a dramatically lower net cost.
Every project is different. The calculator is organized into four tabs so you can adjust exactly what applies to your situation and instantly see how it changes the outcome.
The dollar amounts shown on this page represent one specific example scenario based on an 8,000 sq ft commercial building with a 40% Investment Tax Credit rate, default installation costs, and United Power Large Commercial utility rates. Your actual numbers will be different.
Installation costs vary by location, soil conditions, labor market, building configuration, and project scope. Tax credit eligibility and rates depend on project details, prevailing wage compliance, domestic content sourcing, and your specific tax situation. Energy savings depend on your local utility rate structure, climate zone, building usage, and equipment performance.
This calculator is provided for educational and planning purposes only. The interactive tool allows you to replace every default number with your own real-world figures to see how the comparison changes for your specific project. Always consult a licensed contractor and a qualified tax advisor before making financial decisions.
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