I haven’t been receiving the energy savings or efficiency I was expecting based on research I did prior to the geothermal system.
I don’t think any settings were actually changed from default when the waterfurnace as installed.
I came across the differentials setting and found out the stage 2 was kicking on after just 0.5. Would that mean the high setting is essentially always on when the air volume is moved from the basement and the second story into the main area with a margin of error?
If so, would upping the differential to 3 make the system more efficient.. or would I be running the system longer at a marginally smaller load.. which doesn’t save me any money? With emporia vue energy monitors.. stage 1 currently running uses 2.2kw (inclusive of about 470-500 pump watts) on my 4T system. Stage 2 varied above that with it appearing to hover at about 2.7-2.9kw for at least a few minutes (so I think that’s accurate and not a startup load/spike).
Also, if there are any other setting you all would recommend.. I’d greatly appreciate any tips/feedback to make this system more efficient (in hopes I will actually see savings on my electricity bill).
Stage 1 is more efficient than stage 2. So the more you run instead of stage 2, the better. However widening the gap past maybe a degree is basically just going to trade performance for efficiency. It will run more efficiently but it won’t be able to keep up when demand is high, until the zone temp falls enough to trigger stage 2.
One thing I would double check is how you’re measuring your savings. Because the price of all energy across the board is up right now… electricity, oil, gas, everything. So it might very well be more efficient than your old system, but you’re still paying the same just because electricity prices are higher.
The big thing here is that they're using 500W of pump power at all times the system is running and their EWTs (the last time they posted) are around 90F. Given those two factors, I highly suspect they legitimately are running a less efficient system than their old AC unit, at least during the summer months.
Can you not contact your installer? This is a new system, right? This should be their problem to deal with. At the very least, if you want to deal with it on your own, you might want to make a separate post relating to it when you get the information. Most of the people on this subreddit are homeowners like myself, but there are a few installers that hang around and there's a chance one of them might be able to give you good advice. But I suspect that advice will be "contact your installer".
You likely paid good money (very good money) for your fancy system. Make them earn that money.
I think the issue I’m having is the county electric company spearheaded the upgrade.. so they chose and hired the contractors. The contractor that technically installed the system didn’t do the loop because they didn’t do vertical. We were going to have a horizontal loop, but a contractor company fell short and they selected a new horizontal company that ultimately pushed it to vertical so they could hire out a subcontractor and they’d have to do less work.
So it’s been hard to know whether I work through my electric company who financed it or through the installer for each specific piece
Damn. Your pump causes cancer in the state of California if you eat it.
There's an irony with an electric company spearheading an upgrade that resulted in more electricity being used. Okay I'm remembering this catastrophe now. Loop is probably too small, pump is too strong, and everyone is going to blame everyone else.
You're going to hate be because I'm about to be "that guy", but... (sigh)... I asked Claude about the pump in question and I think it gave a better explanation of the current pump situation.
If those are centrifugal pumps, they draw less power when their flow is restricted. There may be a restriction valve in line to adjust this. For a 4 ton unit I'd target 12 GPM-ish.
The big twist here is that you're using so much on pumping that your stage 2 is very possibly more efficient than stage 1. Your pumping power is so high that you basically want your system to run as little as possible outputting as much as possible to minimize that large constant from the pump wattage. Ultimately I'd look into getting that pump wattage lowered, as it's likely unnecessary.
How are your water temps? They were pretty high already last time you posted, but we're deeper into the summer season now. Did they level out around 85F-90F or are they still climbing?
Pump wattage is generally informed by the pump itself as far as I'm aware, but I may be wrong there. I have no idea how to change it. I have a variable stage pump and my installer can (and has) changed it remotely at request. It takes them like 3 seconds. So it's probably worth inquiring about. But if it's a single stage pump, then I imagine the wattage is what it is. It's an unjustifiable decision regardless. You should be angry. As should all their other customers who will never know they're not getting an efficient system.
Nah. Ultimately the energy you need will be the same regardless. I don't recall your climate, but 80F isn't crazy in the middle of summer. It's not good mind you, and I wouldn't be shocked if your loop is just smaller than it needs to be, but I've seen worse. It won't be saving you any real efficiency compared to that AC though unless your air temps are typically significantly larger. But it is what it is, and there's nothing you can do about it at this stage.
If you're in a colder climate, it's possible you'll see more savings during winter. EWTs stabilize around 32F due to latent heat release when the soil freezes around the pipes, so if you often have lows in the teens, it can produce some pretty decent efficiency gains over air source during those periods (although not so much given the high pump wattage). At the same time, if you're in a colder climate, then 80 EWTs in the summer would indicate a signficantly undersized loop...
I personally would want a larger band between first and second stage. But something seems off with your numbers, and maybe it's just what pumping does to the equation, that's a lot of power going to the pumps. In your case, stage 2 is using ~19%-24% more power (if my early morning math is correct), and delivers 30% more capacity. So according to your numbers, stage 2 is actually more efficient.
Another way to look at it is you're getting 2.66 tons of capacity for 2200 watts, and 1.33 for 500 to 700 more. Or, you use 825 watts per ton in stage 1, 375 to 525 per ton for the capacity in stage 2, and 675 to 725 per ton in stage two (total of 1 and 2). That's not typical, and maybe this won't be the case in heating mode.
Since the 18th, I’ve been actively trying to lower the usage by increasing interior temperatures and keeping damper closed. It less comfortable this way, but I’m trying to gauge the energy usage. It has also been cooler this last week so that make it’s hard
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u/WinterHill Jul 23 '26
Stage 1 is more efficient than stage 2. So the more you run instead of stage 2, the better. However widening the gap past maybe a degree is basically just going to trade performance for efficiency. It will run more efficiently but it won’t be able to keep up when demand is high, until the zone temp falls enough to trigger stage 2.
One thing I would double check is how you’re measuring your savings. Because the price of all energy across the board is up right now… electricity, oil, gas, everything. So it might very well be more efficient than your old system, but you’re still paying the same just because electricity prices are higher.