Open Loop Geothermal is Great But Exclusive

An open loop geothermal heat pump is a superb option for homeowners interested in low-cost, ultra-comfortable heating and air conditioning. Not only can an open loop ground-source system be simpler to install than a closed loop, but open loop technology often delivers the most energy efficient performance available.

Of course, there is a catch.

Open Loop Geothermal is Not One-Size-Fits-All

The main difference between an open loop geothermal and closed loop geothermal heat pump is the nature of the ground installation. A closed loop system relies on a buried network of piping to conduct heat in and out of the building. An open loop geothermal system pumps water from a well, runs it through the system, then dumps it back into the ground. As previously mentioned, an open loop geothermal unit can be highly efficient and doesn't need elaborate piping, but....

Water Quality for Open Loop Geothermal

How high quality is your groundwater? Groundwater with too high or too low a pH level is bad for an open loop geothermal system. Inferior water can cause scaling or even completely corrode and dissolve a heat exchanger. Which, as you might imagine, is not what you want. You really need 'Goldilocks' (i.e. - just right) water for an open loop. When you can't get it, don't bother.

And even if you do....

No Pumping, No Dumping

Numerous municipal governments across the country have made "pump and dump" open loop geothermal units illegal. In many, many places, you can't just pump well water out of the ground, run it through your system, and dump it back out. The government just won't let you do it.

Now, pumping the water back into the well via injection is fine most places, but....

Capacity Needed for Open Loop Geothermal

A geothermal unit on an open loop needs a lot of water to operate. Roughly speaking, it needs about one and a half gallons of water per minute, per ton of operating capacity. To run a 5 ton system you would need 7.5 gallons per minute. Heck, an average system could use a million gallons of water or more in a year!

Which is definitely a lot. Fortunately, that water is not polluted, so it can just go right back into the ground. BUT, if you don't have enough ground water to supply the open loop, which large portions of the country do not, then you have a problem. And that problem is basically unsolvable as it relates to open loop geothermal installation.


So, if you meet all the requirements for open loop geothermal, then great! You can get a wonderful heating and cooling system with ultra-awesome energy efficiency.

But, if you can't, don't worry about it. You can still used a closed loop geothermal, and their efficiency is still way better than any conventional system.

Still Have Questions About Open Loop Geothermal?

Just ask us in the comments below, on Facebook, or on Twitter.

0 comments (view/add)

* All fields required.

Your email address will not be published. Comments will display after being approved by our moderators. Comments may be edited for clarity.