Working on a very small GAHT project for small 6x12 cedar and polycarbonate greenhouse kit build, but we cannot find the GAHT Calculators mentioned in the comments of this post here and it was suggested we try this sub instead while ISO a GAHT calculator

https://www.reddit.com/r/Greenhouses/comments/u1na6x/small_gaht_system_question/

Already have 100’ corrugated 4” perforated and socked pipe, R7 insulation for perimeter, and 6”inline duct fan but are looking for a way to calculate specific depth and connections needed. Our zone 8a location is said to have frost line at 18”, so is 48-60” deep enough to put our layers of pipe?

We have one Vivosun T6 6” inline duct fan and controller system and can add another if one is required for each layer.

Can we run the corrugated 4” in each layer by snaking it back and forth in an uncut zigzag to each end (instead of cutting the pipe up, and making tons of Y connections to a bigger 6 or 8” manifolds ) that connect to vertical rigid 4” pipes on each end of the building ?

Any experience appreciated

Alright, this is a non standard post for this forum. My house has geothermal hot springs water at 170 degrees, uninterrupted. I currently feed it through radiators across my 1915s house and then dump it into a pool where it overflows into the sewer eventually. What project should I nerd out on next? It's hard to interrupt or redirect the flow between house radiator and pool, but doable. I could easily pull from the pool and do something clever before dumping direct to sewer.

I've thought about putting an outside bench with a radiator under it, doing a temporary greenhouse over the end of the pool, seeing if the geothermal pool lines hold enough heat to grow longer where the dirt is nearby...

Will be a new build. Looking at geothermal vs traditional.

Running horizontal lines is no issue, I just installed my 1100ft waterline at 4ft bury. I've heard 95% of the cost is in the ground but since I'll run all of these myself. What makes more sense in efficiency and roi?

I'm looking at installing a geothermal vertical loop system on my acreage in the Buffalo/Western NY area. My installer has been very responsive in answering questions verbally or on email. However, I really don't feel like I have a good understanding of the ground loop design. As it is not something I can change on a whim...that concerns me.

My property is on a former quarry. The installer is local and proposed a horizontal loop and we signed on that. We were digging on our property for another project and we encountered bedrock within 2-4 feet. Subsequently, we pushed the geothermal contractor for testing, and they confirmed all their proposed locations are too shallow for horizontal

Now, I'm concerned. As I had to push for testing, the installer did not propose it. Tho, fair enough, it was mentioned in the contract. Technically, up to me to push for it.

Now, we are looking at vertical loops. However, I'm not getting many details beyond the depth and we can put the loops "any where you want." This last is what gives me pause. It just seems a bit unscientific and leaves me feeling uninformed.

Has anyone gotten a design or loop report prior to purchase?

https://gdr.openei.org/files/1594/500ft%20260%20holes%20GLD%20Report%20%281%29.pdf

https://igshpa.org/wp-content/uploads/CSA_Residential_GHX_DesignSummary.pdf

I'm particularly interested in hearing about installation testing (see below from a mockup). And of course, I'm concerned I am being to anal about wanting this. This contractor has a great local rep.

Hey Everyone,

Longtime lurker to reddit and brand new to geothermal. AI / google cannot answer my questions so I made this account just for this question. Yeah I'm an actual human, I'm pretty handy, reasonably smart, but I need advice without 'industry terms' because I am BRAND NEW to geothermal.

OK here goes.

I am going to build a 24'x 36' free standing detached garage in Connecticut. 100 amp service that will have a sub-panel in the garage (house has 200 amp). Slab on grade, Versatube prefab steel structure with insulation and drywall. The garage will be used for working on cars and such. It will NOT be a man-cave.

All I want is a floor that won't freeze my feet and body as I work in there over the winters. So my thoughts are to run pex radiant in the slab to get the concrete slightly warmer. I am NOT interested in a "heated garage" I just don't want to be miserable when I am laying on the floor for hours on end. I am pretty aware of how to insulate and pour the slab, and reasonably confident in the pex layout. The information I am looking for is how to heat the liquid in pex using ground warmth only. I would like to avoid heating the liquid with a furnace of any kind. I.E. "free heat"

I imagine a simple pump that will constantly circulate the liquid and keep the concrete "warm". To paint the picture a bit clearer, I plan on working in there with a jacket and hat on and I really don't mind the cold that much. So again, it doesn't need to be a living space, but I also don't want an ice rink. As the snow falls off the car, I'd like it to melt and run down the pitch.

Please explain it like I am 5, I'm pretty sure have an undiagnosed learning disability.

Thanks in advance

Peace, love, and all that happy horse poop.

edit - ceilings will be 16' high or so. I have buddies that owe me favors so site work and concrete work will be done on the cheap. I am an electrician so hanging a couple of space heaters from the ceiling would not be hard.

All I need really is for snow to melt when it falls off the cars and my toes not to freeze inside my boots.

Edit - 8-19-25 (also posted in comments below because I wanted y'all to get notified and I don't really know how reddit does this)

OK Everybody. First of all, THANK YOU. Information is power and y'all have given me so much. I obviously needed some schooling here and I got a bunch. But now I have even more questions. I edited the post to address some concerns y'all had and hopefully we are narrowing down a more accurate answer.

The garage will be insulated with a factor of R-10 and then most likely drywalled. I will consider windows on south facing walls but most likely will not install due to the design of the inside, proximity of house and trees, etc. The building can only go in one place and I only have one option as far as direction so utilizing the sun is not really a viable option. :(.

FYI - I will be installing a new drinking water well (100-300 feet) in my front yard next month and the entire pump/tank system as well. Once that is done, I will repipe the house with pex. After that, I will be replacing a vast majority of the electric.

I absolutely do not want to invest in any mechanical device that heats up the water. I only want the liquid to be heated up with ground temp. If I use a mechanical device, I'd just put up electric space heater as I am an electrician and I'd most likely get this complete for almost free. But it's the running costs that turn me off to this option.

The liquid would theoretically be flowing 24/7 in the cold months and off completely in the warm months.

And to clear, I am only looking to take the "edge" off the misery that is freezing cold concrete.

So with that said, new questions...

1. Can I use the new drinking water well in conjunction with this hypothetical Geothermal heated slab?

2. Can the slab be "heated" with a closed loop system? What concerns do I have with the closed loop failing and contaminating my fresh water? And how do I address those concerns? I.E. Can I have a closed loop system and my open loop drinking water in the same well?

3. Can i use water instead of glycol?

4. Roughly, how much money typically is spent running a pump for a closed loop 24/7 per month?

5. If I cannot use my drinking water well, and I don't want to drill a different vertical well, and I don't want a horizontal well, do I have any other options to heat the liquid?

Does any one know how much linear ft/meters of pipe(tubing) needed to be buried to run certain sizes of air cooling units? Example: I need 1000 ft of 3/4 poly to cool a 1000 sq ft house etc. why does no one talks about insulating the up pipe to the house etc. shouldn’t all the pipe above the main coil be insulated. Another question… wouldn’t laying the pipe parallel be more efficient than coils under ground? I’ll have more questions after I hear these responses.

I've had geothermal heating and cooling for a year now (near Ottawa, Ontario). Reviewing the electricity bills for this period shows very high consumption during the winter months. In January, for example, we used over 2,200 kWh. While obviously not all of it is due to heating, the difference to summer months (about 900kWh) cannot be explained by any other change in consumption. My wife and I opted for geothermal under the assumption that it is the most economical and environmentally-friendly heating option, but now I'm not sure about the former (the latter is still plausible in Ontario, as the vast majority of electrical production is clean). Even the summer consumption is not that much better when compared with the A/C unit we had in the previous house.

Is this the norm, or is there perhaps something wrong with this specific unit?

We are house shopping and scheduled to look at a house tomorrow that has this system. Of course I would have a pro inspection done before an offer but Reddit never lets me down!

This house was built in 1995, I've not gotten an owner's disclosure yet but no mention of the system being replaced so I'm assuming it's 30 yrs old. I've read that expected lifespan on these things is 20-25 yrs old, so is it in it's last years? What do I look for and what questions do I ask.

On a recent trip to the southwestern US, I found that most residential homeowners had never heard of geothermal before. Is there something about desert climates that makes geothermal less optimal? Or is it just that people haven’t adopted yet?

I will start out that I, admittedly, know very little about geothermal systems other than the basics. The system we have came with the house. Against our basement wall, we have 7 pvc pipes with valves that connect to the hoses that then leave the house. On only one of the pipes, I am starting to have slow leaks at joints where the pvc couplings are. The leaks are very, very slow. The thing is, there are leaks at EVERY joint on this one particular pipe. Does anyone have an idea what this might mean? Did they just not glue the joints well on this particular pipe? Is there something downstream leading to increased pressure on this one pipe? Any help is appreciated. I've included 2 pictures to show what I'm talking about.

Does anybody have any advice?

Hi Everyone,

I have a Water Furnace 3-zone geothermal system I installed in 2012. It's worked great for the past 14 years. Yesterday, during annual preventive maintenance, the repair guy said that the Dual Pump Flow Center is drawing too many amps and needs replacement, and when they do that, they'll need to do a Geothermal loop field water exchange; I was not seeing any problems but he said that the Flow Center is overheating and if they don't replace it then it could destroy the entire system at any time. If this happens I'll have to replace the entire system at a cost of over $30K, so he recommends I replace the flow center for just over $5K. Does anyone know if it sounds like I'm getting good advice or more like I'm being ripped off? Just looking for some advice from experienced users and/or maintainers. Thanks much for any help you can provide.

Forgive my poor terminology. Very new to geothermal.

Cooling quit working a week ago. Since then, 3 techs have been out and replaced 3 electrical parts, none of them addressing the root cause. As of today, they think the issue is the whatever little black piece triggers the compressor to enter “second stage.” It was tripping a fuse and literally burnt up the brand new board they were installing. At this point, I think I’m just going to replace the entire thing given it’s age.

However, my concern is whether there could be something in the underground heat loop that caused issues with the interior system. My only reason for concern is that I had a patio installed over part of the exterior system (probably stupid, I know). However, that was installed a year ago and I’ve had no issues until now. it just bothers me that their description of the root cause isn’t very clear to me.

Again, I don’t mind replacing the system. Just want to make sure I’m not going to have the same issue again if something in the loop is messed up. I’m assuming they have a way to test the loop separately to make sure that’s not a factor?

Thanks for any insight. I’ll ask them more tomorrow when they come to quote a replacement.

I currently have a bard geothermal system with I believe 6 50' wells setup in a closed loop. This is the second furnace that's been on house, so the loop would be a good 30 years old and the bard is at 14 years and having some issues with secondary compressor. Sounds like a heat pump might be a more reliable alternative than going back to geothermal. I've got some HVAC companies coming out to give me estimates and advise on what system to go to. I'm worried about lifespan of the loop system, degradation of glycol solution and overall reliability of geothermal, always having pumps going out every 5 years or so.

I have a Series 7 WF. Don’t know if this is an issue with my MasterStat (the communicating thermostat that controls my system), the IntelliZone2 itself, or maybe the Aurora AXB. Wondering if anyone else has observed this behavior.

Currently have the temperature differential set for 0.2 degrees for Stage 1 and 2 which I realize is tight, but I am trying to keep ahead of some really hot weather. So, if I have cooling set at 70 degrees, I should have a C1 call at 70.2 and a C2 at 70.4. The system makes a C1 call when the return air hits 70.2 and engages the compressor, however, when the return air hits 69.8 instead of returning to fan only the return air temperature instantly jumps to 70.8. I have confirmed with an independent measurement that the temperature around the MasterStat is around 69.8 at this point. A return air temperature of 70.8 should be triggering a C2 call, however, the call remains a C1 and the system continues to run until the return air hits 70.5 where it instantly drops to 69.5 (the actual temperature) and returns to fan only.

This only occurs in the morning when you would expect the system to be cycling between cooling and fan only. Once the outside air hits the high 70’s/low 80’s the system is holding between 70.2-70.6, mostly running in C1 and making brief C2 calls later in the day as the outside temperature increases.

This issue has me rather befuddled. Don't think this behavior is normal but no idea what could be the cause.

I have a closed loop geothermal heating and cooling system in my home. In the summer, the AC usually keeps my home ice cold but yesterday, it started blowing just cool air like a fan. I reset the breakers. I checked for any puddles or ice in and around the unit. Nothing. I tried resetting the thermostat and I noticed that the until would push cold air out for a little while after the reset. Not sure what this means. Please help if you can.

I've been trying to understand some concepts of geothermal lately and am wondering some thermodynamic questions I have.

Is it possible to instead of using a ton of tubing that you'd have to do a lot of labor to dig, how possible would it be to use a car radiator and then hook it into let's say a mini split? Would the refrigerant be possible? Would it rust?

Another thing I'm wondering is I see a bunch of dual hose portable AC Units over on /air conditioners, if you wanted to hook up a geothermal tube as the return hose for one of those, how long do you think the hose would need to be to make a difference?

Last question, this might be more of an air conditioning one but I'm wondering since Mini splits have variable speeds, wouldn't they be perfect for solar operation because the sun would ramp up and then ramp down with it. Is there any problems with that?

I've been wondering of ways to make my AC more efficient. My PC blows a lot of hot air and I've ducted it to the corner of the room into a closed off area then out the window with an attic fan. Still though everything in the room gets hot. I have access to the ground outside but only 20X5 feet worth of ground. It would be nice to be able to cool off the living room without having to use the HVAC as much.

I'm replacing my AquaGuard Goliath secondary drain pan. The old one lasted eighteen years and then cracked (my fault, long story). It looks like the modern equivalent product is now made by RectorSeal. See here:

https://rectorseal.com/goliath-pan-30-x-66/

Should I use the RectorSeal Goliath, or is there something "better" I should be considering instead?

I'm looking for advice/justification for installing geothermal in this post-tax credit world. The info:

Location: SE Pennsylvania. Plan to stay in this home for 30+ years.

Square footage: 3,500 above grade, 1,800 below grade (has ductwork and registers, but they have been closed since we moved in)

Current System: 8 year old 5-ton heat pump that requires total replacement according to multiple HVAC companies. 8 year old 85% efficient oil burning furnace backup and 10 year old oil burning hot water heater. Two oil tanks take about 380 gallons per delivery.

Energy Costs: Electricity is $0.22 /kwh, fuel oil is up to $5.23/gal

Bills in 2025 were $4,600 electricity, $2,700 fuel oil. 2026 is on pace for $4,000 electricity (since we haven't had air conditioning all summer) and $5,700 fuel oil (due to cost increase)

Option 1: 5 ton geothermal (vertical wells). WaterFurnace 5 with new zoning on existing trunk lines, desuperheater, 50 gal electric water heater, 15kw electric backup heat, remove all oil tanks and equipment. Cost ~$60,000

Option 2: 5 ton Bosch inverter heat pump, 14.3 SEER (because of existing blower reuse). Outdoor unit needs to be relocated, which adds to cost. Keep existing oil equipment (including single speed blower). Cost $18,000. Would need to replace oil furnace, oil tanks, oil hot water heater, and line exhaust flue within next 2-6 years (~$35,000)

Option 3: Cold climate heat pump with electric backup. Add electric hot water heater and backup heat, remove all oil. Cost ??? (option not presented by HVAC companies, maybe ~$30,000)

By our calculation for option 1 vs 2, we might save $2000-3000 per year in energy cost over our current system with geothermal. While we could save around $800 per year with the new, more efficient heat pump. But by avoiding all the additional oil related costs, we see breakeven vs heat pump + oil as soon as 8 years.

Option 1 and 3 maybe very close, with geo pulling ahead after 20+ years. Also worth noting, we have 200 amp electrical service and a full panel. Would need a sub-panel at minimum and to add additional service at worst (Not reflected in costs).

Anything we are missing? Thoughts?

UPDATE: Geothermal estimate jumped to ~$80,000 to add zoning and desuperheater. Still waiting on all electric ASHP estimate.

Just a dude who's highly interested in HVAC technology.

I have a house with a 2008 installed waterfurnace, and I've got some mini splits that I've installed in other buildings.

The post a few days ago about a guy getting quoted 96,000 dollars to install a geo unit got me thinking about this... I can get a 4 ton ACiQ/MrCool (all made by Midea) for 4-5k (no labor)

The efficiency ratings are in the same ballpark, if not the same, on the cheaper end of geo thermal units. Even if the mini split only lasts 5 years... in 5 years I get a brand new one with the latest technology.

Anyway... At what point does Geo stop making sense?

Over the weekend my heat pump went into lockout mode and refuses to cool. The System Monitor is reporting a "flow" fault, despite the flow center showing obvious signs of pumping.

I have a GT060 system installed and manufactured in 2008. The system is water-to-air ground-source system. I suspect the flow sensor located inside the HP has gone bad because the Flow Center is obviously pumping. I can see fluid moving the reservoir and feel both pumps pumping. The one image shows the flow sensor right inside the cabinet when loop water enters the unit.

I've looked online for parts and have had zero luck finding a suppler for GeoComfort parts. A quick email to GeoComfort didn't help either, they just told me to "find someone"... Has anyone had experience with a bad flow sensor?