Open loop vs. Closed loop
In initial meetings, many of our customers have stated that open loop systems are more efficient than closed loop systems. In most cases they’ve heard this from another contractor. This statement is misleading and doesn’t apply to operating costs. I’d argue that generally speaking both systems are equally efficient. The most important factor is which one is the best fit for you. Let’s take a look at both…
“Open loop” and “closed loop” refers to the source. The source side is the location where the heat pump will be extracting or rejecting heat to. The load side is the home we’re trying to heat or cool. Let’s start by looking at the pros and cons for each geothermal source. Remember that efficiency for ALL water source heat pumps exceed that of any other heating system today:
Open Loop Source (“pump & dump” or “once-through”):
Refers to running domestic well water through the system and discharging somewhere
Pros: Cons:
Less expensive install costs Increased well pump usage
(In most cases ) Water quality concerns
Consistent entering water temperature Additional water control valve required
Slightly more capacity in late winter Discharge water location / design required
Closed Loop Source (Horizontal pit or trench, vertical bore, horizontal bore):
Refers to circulating the fluid out through the ground and back through the heat pump in a continuous loop with high density PE pipe
Pros: Cons:
Control over water / brine quality Typically higher initial install costs
No scaling or build-up concern Requires yard space
Less maintenance Lower entering water temperatures (heating)
Zero water usage from well
Zero Energy Consumption from well pump