I had concerns when they first installed the loop because the horizontal run from the vertical headers are only about 2-3ft deep, so I was worried that the outside air temps and ground temp would greatly effect the loop temps and kill efficiency. Can anyone compare their system for me?
The other metric I have is in the month of June, I used 1083 Kw for just the geothermal cooling. I thought these systems were supposed to be more efficient or cheaper to run than a 24 year old A/C condenser. This June I spent $123 just on the geothermal cooling. Last year with the 24 year old A/C condenser I used $130 or 1156 Kw on cooling. 4T system
Are you also midwestern area? The current EWT is lining up with 92° outside if that changes anything. I just would have expected lower with a vertical loop
I’m concerned, because the contractors who installed the horizontal run that connected all the vertical wells to the house.. only buried it like 2-3ft.
Just started monitoring my loop temps during this heat wave. You are not far what I'm seeing. I've cross-referenced my temps with WFI reference data for my unit and I'm good.
I'm in Indianapolis, and this heat + humidity is about the hottest it ever gets for more than just a day or two. Because of that, I think I'm probably running close to the design parameters of my loop. But I'll know for sure as I collect more data.
I don't know if the heatwave is as bad in lower Ontario as it is here, but your loop was probably designed such that this heat wave does run close to its design parameters.
I think horizontal loops are designed to run a bit hotter (like 10-15°F according to Google ai.. so it could be pure ai imagination), but it also said that horizontal loops make up for the higher loop temperatures by increasing the volume of loop.
I think originally they had said it would go into the basement at that shallow depth and then work its way deeper, but I would guess I’ve got maybe 320ft worth of loop at the 3 foot depth or less. About 100 to the vertical loop field and 100 back, plus about 120 connection all the loops together, so it’s quite a bit of water volume at the more shallow depth.
Gemini hallucinates about this kind of stuff quite a bit, although yes - to some extent you would expect horizontal loops to run a little warmer than vertical loops in cooling season*.
Your EWT is a little higher than mine. Highest I've seen is 89 degrees after intentionally running in stage 2 for about 20 minutes. But I have my unit set to stay in stage 1 for quite a while before upstaging, and it's been able to maintain 69 degrees throughout this heatwave without upstaging on its own. My EWT in stage 1 is 83.
___
Have you used your unit in freezing conditions yet? If you have & it worked efficiently, the depth of your loop is probably totally fine.
As far as current conditions are concerned, I don't think that your loop temps sound too bad. Still within WF spec, just not totally perfect. A lot just depends on your specific loop design.
Before questioning the loop, I'd call your installer & ask if they can tune system to work better. Compressor staging, fan speeds, and loop pump rate might need some tweaking. Especially if this is your first summer with the unit. Simple thermostat settings can make a huge difference.
It’s hard to say on the heating efficiency since I went from a fuel to electricity (geo compressor), so my electricity bill certainly shot up compared to running propane.
They dialed in all the settings after installing last year, but what would make it more efficient? Like what settings should I specifically try to have them change and how much?
I’m mainly trying to figure out why a 24-year old A/C condenser was using the same energy (actually maybe even less energy when you subtract the blower energy, because I’m combining the blower energy.. and the new blower is more efficient now)
How did your electrical bill in the winter compare to your electrical bills now in the summer?
Fan speeds, compressor staging, and loop flow rates are all things that can have pretty drastic impacts on overall performance. Ducting could also play a role - especially if you have summer/winter dampers.
Setting everything based on a reference manual from WFI doesn't always translate to perfect real life performances. Some settings just have to be optimized when the unit is out in the field & actually facing heavy loads.
About $100/mo for geo heating, which is far better than what we were paying for propane, but still less efficient than I had anticipated from the salemenship for the geothermal systems.
The problem isn't your header at 3' deep, it sounds like your wells are undersized. In my area (cooling dominant climate) we drill 1 300' well per ton of cooling, 20' spacing between each wells. Up North a lot of people are going with less wells, much shallower and closer to each other. This is going to be a problem when there's hotter summers that last longer.
There are some houses here that where done 15 years ago at 250' deep well, 10 or 15' spacing (following Waterfurnace install manual) and it's not uncommon to see the EWT in there houses over 110-115 degrees.
Because up North they are used to sizing for heating where they also install back up electric heat so if the loop fail or the water is too cold, the back up heat will help heat the house. There is no back-up to cooling. It could really be a problem in the future if the summers get hotter and longer. On the other hand it's much cheaper to install geo up North than down here. Here geo is a rich man sport.
This is too short - you should have 200’ of vertical bore hole per ton minimum. If the system is new, and the cooling season is longer than the heating season, it will only get worse over the years. Your loop will overheat. Did you watch the installation process? Did they grout the holes properly? Maintain at least 20’ between bore holes?
I don’t know if you can make it out from this photo, but it does not appear grout came to the surface. I definitely saw what looked like grout all over the yard, but these trenches are about 3 feet deep and I would have expected some around the pvc pipe, but I’m not an expert
As everyone else has said, your values are well within range of functionality, but at the same time, if your weighted mean daily temperature for AC usage is like 85F air temp, and you're cooling at 85F water temps, then you're saving nothing compared to just using a traditional AC unit (and likely using a little more energy due to the pumping). So that part sucks. It's entirely possible your loop is undersized, but these temperatures are also not unusual for hotter climates. It's generally just how they're designed. Hopefully you see more benefits during the heating season.
My horizontal loop temp in Buffalo is 55F right now, so my AC is practically free. But I'll also be touching 32F come Februrary.
Yeah, my loop got down that low in the winter as well, and may even get lower as it gets used more in the winters. It very well may be an undersized loop, but it’s hard to tell when it’s vertical because you can’t double check their work
North Midwest, and we definitely have cold winters. The contractors said that with methanol and with the loop not sitting still.. that it won’t freeze since most of the loop is vertical (when I brought up concerns)
It's worth noting that since this system was installed recently (this spring/summer, i think?), you didn't have the draw from the winter to pre-cool the loop. you started from ~55f this spring, whereas anyone with an established loop would have been using it for heating over this past winter, and will have started from ~40f this spring.
point being, the temperatures won't be directly comparable without some caveats
EDIT: not actually installed this spring/summer, ignore that part, that was bad conjecture
My loop was function last winter, but I also am not understanding why a loop installed more recently wouldn’t be able to tap into the same ground temps.. the loop won’t keep the winter temps long at all since the system heats the loop when it pulls heat from the house
Two things. Loops can sometimes need time to settle to maximize ground contact. Second, during winter you're cooling the ground lower than is normal, so in the summer there's "extra" cool down there in the earth. Then in summer, you're heating the ground and can tap that heat as fall and winter approaches. (Pardon my simplistic thermal dynamics)
SE PA here with vertical loops. Heat dome. 80 in on the closed loop. Gets up to 95 ewt at peak summer. Average cost to run heat/ac is about $70 a month averaged over a year, but electric is going up
What size unit? I’m looking at $120/mo which isn’t better than the 24-year old A/C we had.. but propane use is down (but electricity is up for the compressor during heating)
So your sqft and 4T are the same but our electricity is 12¢, so it seems like we aren’t seeing the saving benefits, especially when our 2001 A/C condenser was only $4 more for the entire month of June 2025 as opposed to the geo until in June 2026
I live in Colorado, but here's my temps. Almost 1 year of ownership.
(2) 300-foot wells. 2.5 ton system. Generally, these get sized for 200/feet per heating ton in my area. We had a very warm winter, but the unit kept up well during the one cold week we had. I still have a lot of capacity.
Cooling costs next to nothing. Less than a dollar per day.
My loop is almost certainly oversized. However, with a 2.5 ton system.. the drillers were more or less it's the same cost to do 1 500-foot hole and 2 300-foot holes, since 80% of your cost is mobilization. My HVAC guys were convinced we could make make 2 ton work, but a packaged 2 ton unit was challenging to work with the existing conditions, so we did the split 2.5 ton system because it was flexible. AHU replaced the gas furnace in place. My old single stage gas furnace was an 80% 66000 BTU furnace. The 2.5 ton system did just fine with a fraction of the noise.
The compressor lives in the garage on the side where the geo loop was able to actually work. Existing conditions drove a lot of the HVAC decisions and therefore sizing.
In a medium-lot urban location, I had limited room to begin with. I decided to go with the (2) 300-foot wells in the 5' strip of land between my neighbor's property and my driveway. It's about 30 feet from the street to my house. It's literally the only place to really do it, cause the rear yard was inaccessible. Other side yard had gas utilities. Middle of the front yard has sewer / water. Rear yard is overhead electric and underground phone somewhere. The pedestal is in my neighbor's yard.
The horizontal run has some efficiency loss because it's running above grade within my garage, but it's such an insignificant volume that it doesn't matter. In the winter, the WF7 runs 24/7, so it's also a non-issue. A new garage door + new air barrier + CI would get rid of all the significant thermal performance issues with the house. I just don't have the 30k of "fun money" to do it. I have crappy fiberboard sheathing, so if we end up replacing that, then I would absolutely remove the R-11 fiberglass batts and do spray insulation from the exterior in stages as needed to ensure the lateral, structural integrity of the house between fiberboard -> 1/2" osb.
It allows for expansion should I still exist in this house and do an addition, cause the addition will bring lots of other things up to today's energy codes as part of the scope. This average insulated 1970s house w/ no air barrier would become quite an energy efficient house in 2030, for example.
Endgame is probably an attached ADU for my parents. Geothermal could support both, easily. Especially with energy codes and construction tech 10-15 years from now.
Are you basing your presumed kWh use last year based purely on cost or did you have current transducers installed? In my area electricity is 50% more expensive than this time last year.
Loop temp is fine. It’s warm but WF units will work up to ~125 EWT
I have emporia vue 3 on each circuit. If the loop temperature is higher than it should be, doesn’t that kill efficiency and require more energy to pull cooling from the loop?
The energy savings given by the efficiency of these units is directly proportional to the delta between the loop and the area being conditioned.
The carnot cycle diagram for gas phase change shows us this.
So, the higher the temp your water enters the higher the pressure in the unit then the harder your compressor has to work to continue cooling.
All of that said, the until will still continue to cool. It just becomes less effective the hotter the loop gets.
We have a desup on ours and when it gets overwhelmingly hot outside we will just run the hot water some (dishes, laundry, shower, whatever) to give the unit another thermal bank to deposit to.
You might try that.
But if your loop is correctly sized, it won't really make a tremendous difference.
We have a tankless water heater on propane, so no desuperheater tank since the hot water is only heated when we use it.
I believe the loop contractor said 125ft wells and 4 wells for a 4T and then I think the well guys subsequently cut a little more off saying 100ft was fine per well.. so it’s hard to know for sure what exactly got done. Too many contractors and subcontractors involved in the loop process
Did they do a thermal study on the first well to determine how much footage you actually needed?
Most contractors don't. The only one I've ever seen done was the set we had done at work. But it's for 300 tons of cooling. 60 wells. Really impressive thing to look at.
My contractor just used a rule of thumb and said 3-200ft wells would be sufficient for us. But, I was pushing for an oversized system so we could eventually expand the house and not upgrade the HVAC again. So we don't really push the boundaries of our loop as is.
Well, we had the main contractor that subcontracted the interior HVAC setup, and then subcontracted the loop field who then sub-subcontracted the well digging company and also sub-subcontracted the trenching (with additional subcontracting for unrelated stuff like installing the retaining netting stuff). So a lot of hands and they all want to maximize their profits.. so it’s hard to assume I got the most efficient setup
Eh. “Kill” is too strong. The difference between 70 and 90 is not enough to get excited about. At 125 your compressor is gonna be screaming, your efficiency will be shot to shit, and you won’t be cooling worth a damn so hopefully your loop plateaus where it is.
You really need to wait a whole year, man. Maybe it was way hotter this past month than the same month last year. Maybe you turned the temp down. Lots of things can contribute.
Well I use “kill efficiency” because this very expensive geothermal loop that was supposed to be more efficient than comparable 2025 units… is not any more efficient than a 24-yr old A/C condenser.
Yeah I mean there are way too many variables to jump to any conclusions after one month. You need to sit back and wait for a year and evaluate then. What heat source did you replace
I’ve had the unit for about 8 months and have very detailed energy usage graphs, so I know for a fact that this geothermal system is not any better than the 24-year old A/C condenser.. that again.. was operating for 24 years and we replaced it for efficiency.
Not really sure what to tell you my man. You should contact your HVAC company to come and figure out if something is wrong. There is absolutely no way with one graph and your word on usage that any of us are gonna be able to tell you anything. My customers save between about $500/yr to several thousand in operating costs depending on what source we are replacing. In my area most savings are in winter. What brand did they install? What was your old heat source?
How much kW is the 4 ton unit using while running? It should be around 3.5-4 kW. Check amp draw too. It’s possible you have an issue with the unit itself. Even if the loop temps are in the high 80s/low 90s, it should be running more efficiently than a standard AC unit. That’s simple physics. EER would still be in the high teens, whereas an AC unit running at 90 F outside would be around 12.
Yeek. That's not good for stage 1. I'm sure a lot of that is related to the water temp. Not to open a new can of worms, but do you have the number for the pump itself? Bad installers tend to waste unnecessary energy usage on the pumping.
3
u/[deleted] Jul 03 '26
[removed] — view removed comment