What is a pond / lake ground loop?
A pond / lake ground loop is a series of plastic pipes filled with heat-transfer fluid and submerged in a nearby pond or lake with adequate size, depth, and flow. The loop connects to an indoor geothermal heat pump and uses the pond or lake water as a heat source or heat sink.
It’s also a type of closed-loop geothermal system. That means the heat-transfer fluid continuously circulates in a closed loop that’s filled just once and used again and again in a closed loop! That means that the heat-transfer fluid continuously circulates: no fluid can escape, and no outside materials can enter.
How are pond / lake ground loops installed?
To install a pond loop, a contractor will simply submerge an adequately-sized piping system in a body of water. Similar to a horizontal ground loop system, it’s common practice to coil the pipe in a slinky
shape to fit more pipe in a smaller area.
How large does a pond or lake need to be to install a ground loop?
The ideal surface area is determined by a home’s heating and cooling requirements, but on average, the pond or lake should be at least an acre across. Experts recommend using a pond loop only if the water level never drops below six to eight feet at its lowest point to ensure sufficient heat-transfer capability.
Though pond loops work very well in cooling-dominant climates, be cautious when installing these systems in heating-dominant climates, like upstate New York.
Are pond / lake ground loops safe for the environment?
If properly installed, pond / lake ground loops will not adversely impact the surrounding aquatic system because they’re a closed loop system. Nothing comes in, and nothing goes out.
How much do pond / lake ground loops cost to install?
Pond / lake ground loops have the lowest potential installation cost of all ground loops. They don’t require drilling (like vertical ground loops) or extensive trenching (like horizontal ground loops). An installer simply runs header pipes from the geothermal heat pump to the nearby pond or lake to install pond / lake ground loop.