Ground Loop — Geothermal Piping and Repair Guide Home

A ground loop is the buried pipe loop in a geothermal heat pump system that exchanges heat with the earth to provide heating and cooling.

Ground Loop diagram — labeled parts, dimensions, and installation context

What It Is

Ground loops circulate water or an antifreeze mixture through buried piping so the geothermal heat pump can pull heat from the ground in winter and reject heat to it in summer. The earth stays at a relatively stable temperature compared with outside air, which improves system efficiency.

The buried loop field is the most site-specific and difficult-to-replace part of a geothermal system. Loop design has to match the soil conditions, available land, and the home's heating and cooling load.

Types

Common types include horizontal loops, vertical bore loops, pond loops, and open-loop well-water systems. Closed-loop systems are the usual meaning when homeowners refer to a ground loop.

Where It Is Used

Ground loops are used on geothermal heat pump systems serving houses, schools, and commercial buildings. The piping is buried in yards, drilled into deep boreholes, or submerged in suitable water bodies.

How to Identify One

Most of the loop is hidden underground, so homeowners identify it by the geothermal heat pump inside, loop header piping entering the building, and records showing horizontal trenches or vertical bore locations. Low loop pressure or repeated service calls can hint at loop problems.

Replacement

Replacement is uncommon but difficult when a loop leaks, was undersized, or was damaged by excavation. Repairs often involve leak tracing, pressure testing, and targeted excavation rather than full system replacement.

Ground Loop — FAQ

Does a ground loop use groundwater directly?

Not in most closed-loop systems. The same fluid circulates through sealed piping, while open-loop systems use well water and are a different configuration.

How long does a geothermal ground loop last?

Properly installed closed loops can last several decades, often longer than the indoor heat pump unit. The buried piping usually outlasts the mechanical equipment inside the house.

Can tree roots damage a ground loop?

They are not the most common problem, but excavation, settling, and poor installation are bigger risks. Accurate loop mapping matters before future digging on the property.

What happens if a ground loop leaks?

System pressure drops, heating and cooling performance suffers, and the loop may need specialized leak detection and repair. Because the piping is buried, repairs can be disruptive and expensive.