DIY geothermal

DIY Geothermal – Should You or Shouldn’t You?


You’re a ‘do-it-yourselfer‘. You do your own plumbing, home improvements, and even change the oil in your car. You’re interested in geothermal heat pumps. Obviously, a DIY geothermal install would save you money, but is it a good idea? Should you attempt it or are geothermal heat pumps just too complicated for even gifted amateurs?


Is DIY Geothermal Installation a Good Idea?


The answer is a little complicated.


Working with the interior half of a geothermal heat pump system is similar to installing any conventional HVAC system. Obviously, there are some technical differences, but nothing obnoxiously complicated. You need a location for the pump, convenient connections to the interior ductwork, and easy access to the exterior ground loop.


There is electricity to consider, of course. Any good electrician should not have a problem connecting a geothermal unit. If you know your way around wires and utility boxes, this too is an area you should be able to handle.


These two DIY geothermal aspects, interior and electrical, are fairly straightforward. They are not, however, the end of the story.


Mother Earth and the Buried Loop


Before you begin any DIY geothermal project you have to consider what sort of ground network you’re going to use. The ground installation type will determine how much earthwork is required.


Still, no matter what style ground loop you use there is always going to be some digging involved for any geothermal heat pump system. If there wasn’t, it would be much of a ‘geothermal’ system now would it?


Horizontal Network


Horizontal installations are quite common, since it’s easier to dig over a broader surface area than to dig deep vertical shafts. That doesn’t mean horizontal geothermal is something to take lightly. Even relatively shallow excavation, about six feet or so in our case, can be dangerous.


If you don’t know how to operator an excavator or don’t have access to one, then horizontal DIY geothermal is probably out of your reach. You can do a lot of it yourself, true, but at the end of the day you’ll need to hire a contractor to dig the necessary trenches.


A word of warning: if you’ve never used heavy digging equipment, do not attempt this part of the install alone.


Vertical Installation


The main alternative to a horizontal loop is a vertical loop. As you probably guessed, vertical loop geothermal uses a contained pipe network buried vertically instead of horizontally. A vertical install may use a single deep shaft or a series of slightly shallower vertical shafts.


Now, when we talk about digging vertically we are talking about digging much deeper than we would with a horizontal install. A vertical installation shaft will require sophisticated excavation equipment of a type used mainly by well digging companies. Unless you happen to own such a company, you’ll need to contract this service.


You cannot dig the necessary vertical shafts with a shovel, and it would be exceptionally dangerous to attempt. So, don’t.


Pond or Lake Loop


When it comes to DIY geothermal, the easiest installation available to most homeowners is going to be a pond or lake loop. These systems are pretty simple. All you have to do is submerge the heat exchange piping into a suitably deep pond or lake.


It really is just that easy.


Now, some digging will be involved. For aesthetic and pipe protection reasons, you’ll want the connections between the lake loop and your home to be buried. This particular connection does not need to be particularly deep, so it is within the capabilities of most DIY’ers. A foot or two, and you’re good.


That doesn’t mean it won’t be tiring digging a shallow trench out to your pond, but it is far less complex than a 300 ft vertical shaft or a couple hundred square feet of 6 ft trenches.


The downside to this DIY geothermal installation is that most people don’t have a convenient lake or pond next to their house. Obviously, if you don’t, you can’t use this method.


Open Loops


The final option open to geothermal homeowners is an open loop installation. All our previous examples used closed loops in which the geothermal heat pump operated as part of a self-contained system. An open loop install is the opposite of that.


Geothermal open loop systems interact directly with well water in order to heat and cool your home. They’re the most inexpensive type of installation, but they’re not available to everyone. Many municipal and county governments forbid ‘pump-and-dump’ operations even though this type of geothermal operation does not pollute in anyway whatsoever.


If you can install a geothermal open loop, you probably already have access to a well you can use. If you don’t have access to a well, then, obviously, you’ll need to have one dug.


I’m going to assume that average American DIY’er is not capable of digging their own well. You’ll need to hire someone to do that.


So is DIY geothermal possible or not?


Yes and no.


Yes, some people will be able to install their entire geothermal heat pump without specialized help. And no, because many people will need to hire specialized contractors or heavy equipment to complete the installation process.


55 thoughts on “DIY Geothermal – Should You or Shouldn’t You?”

  1. Try again Does the 5 ton unit come with an internal pump for recirc the closed loop water?

    also does the hot water heater option have a control to turn the external circ pump and a temperature switch to cut of the pump when the water gwets too hot

    1. The 5 ton unit does not have an internal flowcenter, but an external flowcenter can be easily added.

      The desuperheater activates when the unit does. There is not a temperature switch to cut off flow for high water temperature, but that would only occur if there was a problem somewhere. Which would mean the safety switches on the main unit should have already activated.

      Does this answer your questions?

  2. I purchased a GEO Cool system 5 ton with a 2 stage pump for my new house construction with the intention of doing a DIY. I have a large excavator so laying the piping is a piece of cake, but the system did not come with *ANY* instructions on how to do the internal connections. For example, the intake and return manifolds.. do they do on the wall inside the furnace room? Or outside the house? Is there a link to a step by step instruction guide? The installation guide on your website is not detailed enough, are there visual instructions available of at least what the unit should look like once fully installed and working? Thanks for your help!

  3. I just installed a GeoCool CFX036 for the main floor of my 3,000 sq ft home. Upstairs has a 2.5 ton ASHP and the 3.0 ton GSHP is now installed downstairs. My unit is in the basement, which is unconditioned. I have 3 600′ horizontal loops buried 6 ft down. When I initially started the unit, i was getting 88 degree air at the first register. We had 15 degree overnight temps a week or so ago and the unit maintained 70 degrees inside. I’ve noticed that the supply temp at that first register has been dropping and I’m seeing less drop in the LWT than when I first started it on 12/23/15. Now it’s not as cold and the unit can’t maintain 70. The desuperheater is doing it’s job as the holding water tank has 100+ degree water. I don’t have my P/T port temp and pressure gauges yet so I don’t have good numbers for that yet. I hope to get the P/T gauges in a day or so. Do you think I could have a refrigerant leak? Any comments or words of encouragement are appreciated! Thanks for your time.

    1. Hmmm….okay. So, obviously, it’s always hard to diagnose these things without being there, but a few things do stick out.

      It sounds like the unit is drawing more heat out of the ground than is being replaced. Running the desuperheater could be compounding the issue. Basically, you’re splitting your heat up between interior air and water heating. Disconnecting the desuperheater for the rest of the winter could solve part of the issue. Not ideal, but viable.

      The desuperheater, however, is only a symptom of what is probably the real problem. I believe it most likely is NOT a refrigerant leak.

      I suspect that when the ground loop was installed, the proper time was not taken to ensure that the backfill was properly settled. If you just push dirt back over the loops and don’t pack it down firmly, this sort of thing can happen. All the loose earth increases air flow which means the ground is not going to deliver the type of insulation it normally would. That could be why you’re not getting the kind of heat transfer you would expect.

      Proper cover is an easy thing to overlook. If you install your geothermal unit in the spring or summer, this isn’t a big issue. There’s plenty of time for the ground to settle naturally before you get into low winter temperatures. From what I gather, yours was installed relatively recently, and if the dirt was not packed in like it should have been, that could be why you’re getting these issues.

      The good news is that next winter you should not have this problem. The ground will settle naturally in the coming months. The bad news is that this is not a problem with a quick fix right now. It is not really feasible to dig up all that earth and redo it properly.

      Again, I don’t know for sure that’s what is causing the problem. It could always be something else, but from what you’ve described it seems the most likely explanation.

      1. Thanks for the reply. When I backfilled, I actually filled with about 2 feet of dirt and then wet it down and let it sit for a week or two because it was forecasted that we were to receive a lot of rain. We did receive about 3 inches of rain but it was a downpour and not over a period of time. I suppose the loops are still settling in. I expect to receive my P/T tools any day and can get some pressure and temperature readings to verify if things are within range. I’ve read many good things about GeoThermal and I tried to be very thorough in making my decision. Hopefully my soil is suitable for good heat transfer. Best wishes and thanks for your time.

        1. You definitely did it the right way. If you can’t get it figured out, please let me know. I’ll have someone from tech give you a call.

          1. I have some operating information that may be beneficial for you to make an assessment about my unit. This morning we left around 6:00 AM with an outdoor temp of about 27. The thermostat was on 72 and the indoor temp was 70 (I don’t have aux in the unit). When we got home about 11:00 AM it was 64 inside. I checked the unit and it had a low pressure fault. I restarted and it went down again within just a few minutes with a low pressure fault. I decided to turn the unit off for a while. Latter in the day I turned it back on when the temp was 50 outside and the unit has brought the temp back to 72. I took measurements with the desuperheater circulator pump off. Outside air 50, return at unit 69.8, supply at unit 89.0, loop ewt 36.6 and lwt 31.9, PSI in 12.0, PSI out 7.0. (according to CFX036 chart, flow may be low.) Does this provide enough info. for you to make any assessment about my unit? I’m concerned about the low pressure faults. This isn’t the first time I’ve got the low pressure error. Thanks for your time.

  4. The Geocool warranty states that it only applies to systems installed by a licensed HVAC contractor. If an internal part fails within the warranty period will you really refuse to replace it because I installed the unit myself?

    1. The main situation in which we would not cover the warranty is if it was clear the unit was damaged due to something the customer obviously did deliberately. Otherwise, we will always work with the customer to get the problem solved.

      1. Are you saying that Geocool will provide free replacement parts for units that were installed DIY unless there’s evidence of deliberate damage?

        1. Failure, damage or repairs due to faulty installation, misapplication, abuse, improper servicing, unauthorized alteration or interruption of electrical service will not be covered. Basically, if the unit was installed incorrectly which led to the equipment failure, we will not cover that whether it was installed by a licensed HVAC technician or not. If everything was done correctly and our component simply failed, we are going to make that right.

  5. I am planning on switching to a 2ton unite. I am not sure if I will use a ground loop or well to well. I have 2 concerns 1 my water ph 7.2 is that to high? 2 I want to get hot water in the winter if possible should I get a larger unite to do this?

    1. 7.2 pH is edging very close to the limit. If you live in the Southern US with typically warmer ground temperatures, you may want to go with a ground loop. For your hot water question, the best way to get winter hot water is not with a larger unit. A desuperheater can provide you with hot water. Bear in mind though that a desuperheater will provide hot water most efficiently in hot weather during the heat pump’s cooling cycle rather than in winter when the two would be dividing the heat from the ground.

      1. I live in new Jersey. Is making hot water during the winter still more efficient then using my eletric water heater? I could get the loop in ground water if it is in ground water how long does the loop need to be for a 2ton unite.

        1. Direct electric heat is really expensive, so it is hard for me to imagine a scenario in which an electric water heater costs less than using a desuperheater. As regards the size of the ground loop you need for a 2 ton system, I can’t be certain. The appropriate size will greatly depend on not just the size of the unit, but also local soil and weather conditions. I do think that since you live in a more northerly state a well connection may be viable.

          1. My soil conditions are sandy pretty much like beach sand and no clay and will be in ground water at 6 ft. I have two wells so that is a possibility but my concern is the cost of running a 7amp 120v well pump. I also have to share it with my water supply for the house so I would likely have to add a second pump. I am guessing keep one at 10psi and the other to supply the house.

  6. I recently purchased the Geo Cool 5 ton unit with the intention of installing a hrizontal ground loop system. However I was told by a local HVAC professional who told me that because part of my property is a swamp and my water table is really high (I have 2 ponds and the water level is so high i’m unable to have any more than a small crawlspace) that I should do an open loop system taking water from a well extracting the heat in the system then releasing the cold water into one of my large ponds. I would assume that instead of using the 3500 ft of piping you supplied and running it out in my yard, I would just need 5 much shorter lines the draw directly from a well, and then the output is 5 additional lines that go directly into my pond. Is this doable with the GeoCool 5 ton system with a 2 stage pump?

    1. All GeoCool geothermal heat pumps should work great on an open loop, so go for it! Plus, you’re going to save a fortune on installation costs.

  7. Hello I have your GCHP01041H-LE-A-HR-TS unit I am DIY installing. I am having a hard time figuring out how to safely hook up the Desuperheater function. I have been unable to find a external flow center kit other than one Bard makes which is GVDM-26. As I understand it I need to meet the following requirements. The circulation pump should only run when the GeoCool unit is running, the circulation pump should turn off when water temp in my hot water tank hits 125 degrees, the circulation pump should turn off when the water temp out of the Desuperheater drops below 100 degrees (prevent reverse cooling). Do you have a kit or recommend one? Can I use the Bard pump kit with your product? Lastly when the pump turns off at 125 degrees is there any problem with the water still in the Desuperheater boiling or getting to hot and damaging something (I will have a expansion tank in the loop for the pressure variations)?

    1. Joe, can you send me an email with a good contact number? I would like to have someone in our technical support department give you a call. I’m personally unfamiliar with Bard’s products, so I don’t want to give you incorrect information. Please email me at along with the best time to reach you. Thanks!

  8. Doing a DYI install of GCHP01041V-LF-A-HR-TS unit with the superdeheater. Do you have a recommended piping schematic for the superdeheater using one 50 gallon electric waterheater? Also it looks like I need to purchase a circulation pump with the ability to turn on and off when temperature exceeds 125F. Is that correct? Any recommendations on a circulation pump that will do that?

  9. I have purchased a 3 ton Geo cool system with the superdeheater. What type of pumping control center do I heed to connect superdeheater to my water heater?

    1. The desuperheater circulation pump we normally use is the same one McQuay uses – the Grundfos UP15-18B5. This is a 220v pump we wire to the switched side of the contactor. Flow rate is around 5gpm, which must be adjusted to give a 12F water temp differential thru the desuperheater. Hope that helps!

  10. For those DIY folks that want to run an open loop, but have terrible water, here is what I did. I created an intermediate closed loop that is very small and filled with an antifreeze mixture. It uses a small pump to circulate the water. It rejects heat to a relatively inexpensive water to water plate chiller. When the ground water plugs or corrodes the plate chiller it is easily replaced as it is just plumbing connections and no refrigerant is involved. The hardest part is figuring out how big a plate heat exchanger you need.

  11. I’m down the final connections with my geo system on my new house and have run into a snag with the electrical. It’s pretty standard how the main power connects to the main unit and how the unit connects to the thermostat. However, connecting to the geo pulse circulation pumps is making me scratch my head. I have a 2 stage pump and each pump has two white wiresults able to connect to something but the main unit doesn’t seem to have anywhere for them to connect and again the installation instructions are not clear on how to connect the water pumps to the main unit. Clarity on this issue would be greatly appriciated. Thanks. If pictures are available please send to

    1. The GeoPulse pumps are normally wired to the switched side of the contactor in the unit- when the contactor closes to send 220v to the compressor, it will also be sending 220v to the pumps.

      1. Ok that makes sense. But the issue is that there are 2 pumps. If I could get a diagram as to how to exactly hook these two pumps up that would be great

        1. The pumps are both wired to the same 220v source circuit – they will both run at the same time whenever the compressor runs. We do not have a specific wiring diagram since this is pretty much standard 220v wiring. If you are not familiar with 220v wiring it would be best to find someone to help with both the incoming power wiring as well as the wiring to the GeoPulse.

          1. Thank you the information you provided allowed me to connect the pumps. Final question. The installation guide makes no reference to an orange wire for the thermostat yet there is a loose orange wire in the unit. What is the purpose of this wire?

          2. The orange control wire is to be connected to the Y2 terminal on the thermostat. It is 2nd stage compressor. There should have been a wiring diagram included for the new 2 stage units.

  12. Looking through the spec sheet, the GPM seems to pertain to a closed loop system. For an open loop how many gpm for each stage on a two stage 3.5ton?

    1. It will be typically be 3 GPM per ton which equates to about 10.5 GPM on a 3.5 ton. However, what it really needs to be is whatever is necessary to reach a temperature differential of 10-12 degrees.

      1. Ok thank you. I have the unit nearly finished but I noticed in the manual I received with it, the wiring diagram does not illustrate the aux heat. Is there an updated diagram reflecting this? The diagram that came with the unit doesn’t show the aux light, or connections. I have a 15kw in duct heat strip with three control wires, where would these hook into?

        1. That would probably connect to the thermostat, but I want to connect you to someone in the tech department to make sure. You can call tech support for this unit at 800-360-1569 x300 or you can give me a phone number, and I’ll have someone call you.

  13. Can you please tell me what size recirculating pump is required for a 3.5 ton water to water unit with an 80 gal storage tank? Also, is there a manual available so I can run my piping etc. prior to setting the unit?
    thank you

    1. It would be hard to know without more information. I recommend you talk to Jacob, one of our geothermal experts, at 270-575-9595 x103. He can get you lined out.

  14. I am starting my research on installing a geothermal DIY style into a house I am remodeling. My main question at this time is what is the best size unit to use. I understand this depends on many different factors. I didn’t know if there was a guide or a certain “code” that you would recommend I follow. The house is a single story with a half basement. sq. foot including basement is about 3000.

    1. The best thing you can do is hire someone to run a heat load calculation on the house. They can tell you the HVAC capacity required, so you can make an educated choice. Some utility companies can provide this service through efficiency improvement programs.

  15. I just put in a 3 ton Geocool water to air unit and I’ve been dealing with low pressure lockouts. There is plenty of antifreeze flowing through the unit, but just to be sure there was enough flow I even tried changing the pump and the check valve. I have wye strainers on all of the pipes and nothing is clogged. When the unit is working I get a 21 degree delta T on the airflow. The return air was in the mid 60s and the discharge air was in the mid 80s. The entering water temperature is usually 55 to 58 degrees and the leaving water temperature is usually around 48 to 50 degrees. I’m not sure what the problem is. If I let the unit sit overnight and then turn it back on in the morning it will work again for a day or two and then go back to the constant low pressure lockouts. I have a vertical loop with five 360′ wells, a Geopulse M-Flow flow center, and Grundfos UP26-116F pumps. I have a second Geocool 3 ton water to air unit for the second floor and a 3 ton water to air unit as well, but because of the issues with the first floor unit I have not been able to work on the other units yet. Could you please help?

    1. I have another update. I let the unit sit overnight last night and when I turned it on again this morning I still had a low pressure lockout after a minute or so of run time. I changed the unit to cooling mode and ran it for around 10 minutes with no problems and then switched it back to heating mode and I did not have a low pressure lockout.

  16. I installed a geocool 5 ton unit with the complete install kit. On cooling mode I get low pressure lockouts. Sometimes within minutes of of start up other times it may cool gor a few hours. Incoming water 62 degrees outgoing 70 degrees. I have plenty of air flow but the condenser is icing over. Is it possible the unit is low on refrigerant?planning on having a tech vacuum down system and recharge to 65ounces of 410a.

    1. If you have adequate air flow and the water differential is less than 10F then the most likely issue is low refrigerant charge. It should not be necessary to evacuate the system- if the tech can check superheat and adjust charge to 10F that should be sufficient. He will need to check the Schrader valves for evidence of a leak and check for any other signs of a leak.

  17. I have a 5 ton geo cool. Its on heating mode and just came home and low pressure light is on. Unit is working, but not sure its heating well enough. What does this mean and what should I be doing. Thx

    1. The yellow LED is low pressure compressor lockout. This can commonly result from either insufficient water flow thru the heat exchanger or from low refrigerant. Resetting the unit should clear the fault, but then a tech will need to determine the actual cause.

    1. In terms of environmental ethics, a geothermal heat pump is a superior choice to a traditional air conditioner, since the geothermal unit will operate far more efficiently.

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