LEARNING HUB

Geothermal Learning Hub

Beginner-friendly guides to geothermal heat pumps — from first questions to confident decisions. No jargon, no sales pitch.

34+Learning Guides

4Learning Modules

$0Free & Independent

12Key Terms Defined

8FAQs Answered

YOUR CURRICULUM

Four Modules, Zero Jargon

Start at Module 1 or jump to what’s most relevant. Each module builds on the last.

Module 1

Geothermal Basics

What geothermal energy is, how the ground stays warm year-round, and why it’s different from solar or wind power.

Module 2

Costs & Savings

Real installation costs, operating savings, payback timelines, and every incentive still available in 2026.

Module 3

Is It Right for Me?

Property requirements, climate considerations, soil types, and red flags that make geothermal a poor fit.

Module 4

The Installation Process

What to expect from site survey to commissioning — timeline, permits, disruption, and red flags when hiring.

QUICK REFERENCE

12 Key Terms, Plain English

The terms you’ll encounter most — defined without the textbook.

Ground Source Heat Pump (GSHP): A heating and cooling system that moves heat to and from the ground rather than generating it by burning fuel.

Ground Loop: Buried pipes filled with a water-glycol solution that circulate heat between your home and the earth below the frost line.

COP (Coefficient of Performance): Efficiency ratio: a COP of 4 means 4 units of heat delivered for every 1 unit of electricity consumed.

EER / EER2: Cooling efficiency rating. Higher is better. Geo systems typically achieve EER 15–25 vs 12–16 for conventional AC.

Closed-Loop System: Ground loops where the same fluid circulates indefinitely, never contacting groundwater. The most common residential type.

Open-Loop System: Uses actual groundwater (a well) as the heat source/sink. Often more efficient but requires adequate water availability.

Manual J: ACCA’s load calculation standard. A properly sized geo system must be based on a full Manual J — not a rule of thumb.

IGSHPA: International Ground Source Heat Pump Association. Certifies installers and sets the standards for design and installation.

Vertical Loop: Ground loops drilled 100–400 ft deep. Needed when horizontal space is limited. Higher upfront cost, smaller footprint.

Horizontal Loop: Ground loops trenched 6–10 ft deep. Lower cost but requires roughly 0.5 acres per ton of heating/cooling capacity.

Loop Field: The area of land (or water body) where ground loops are installed. Size depends on heating load and local soil conductivity.

Desuperheater: An optional add-on using waste heat from the geo system to preheat domestic hot water — cutting water heating costs 40–60%.

Run the numbers before talking to any installer:

Cost Estimator ROI Calculator Incentive Finder Find Installers

COMMON QUESTIONS

What Homeowners Ask First

How does a geothermal heat pump actually work?

The ground below the frost line stays at a constant 45–75°F year-round. A geothermal heat pump uses buried loops to extract that stored heat in winter (and dump heat in summer), then amplifies it with a compressor — just like a refrigerator in reverse. Because it moves heat rather than generating it, it’s 3–5× more efficient than gas or resistance heating. Read the full explainer →

How much does it cost to install geothermal?

Most residential installations run $20,000–$35,000 before incentives. Costs vary by loop type (horizontal vs vertical), home size, and local drilling rates. With state incentives — still available in 20+ states — net costs often land in the $15,000–$25,000 range. See the complete cost guide →

Is geothermal worth it in 2026?

For most homeowners with adequate land or drilling access and heating loads above 40,000 BTU/hr, yes — payback periods typically run 7–12 years with operating costs 50–70% lower than gas. The federal 30% tax credit expired December 31, 2025, but many states still offer significant incentives. Run your ROI →

Do I need a lot of land for geothermal?

Not necessarily. Vertical loop systems require only a small footprint — a 2,500 sq ft home typically needs 2–4 boreholes, each about 18 inches wide. Horizontal loops need more space (roughly 0.5 acres per ton) but cost less. Pond and lake loops are also an option if you have water access on your property.

How long does geothermal equipment last?

The heat pump unit typically lasts 20–25 years. The buried ground loops are warranted for 50 years and in practice last indefinitely — there are systems installed in the 1970s still operating today. This lifespan is a major factor in geothermal’s 20-year cost advantage over conventional HVAC.

Can geothermal replace my existing furnace and AC?

Yes. A properly sized geothermal system provides both heating and cooling through a single unit connected to your existing ductwork. Most homes go fully electric, eliminating the gas furnace entirely. Many installers add a desuperheater to handle 40–60% of domestic hot water heating as well.

What’s the difference between geothermal and an air source heat pump?

Both move heat rather than generate it, but air source units exchange heat with outside air — which gets cold in winter — while geothermal uses the ground, which stays stable year-round. This makes geothermal 20–40% more efficient in cold climates and eliminates the efficiency drop-off below 20°F. Full comparison →

How do I find a qualified geothermal installer?

Look for IGSHPA-certified contractors. Ask for references on comparable projects, verify they pull permits, and confirm they perform a Manual J load calculation before sizing. Our directory lists verified installers by state with credential information. Search the directory →

Guide

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