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Electrical monitor

Ryan Lewis - Zone 4A | Posted in General Questions on

On the site here I saw an electrical monitor advertised. It communicates over Ethernet and it can measure electricity circuit by circuit. It is not the Sense monitor, which I own but doesn’t do a great job of staying connected to WiFi.

Does anyone know what it’s called?

The list price was much higher than Sense.

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  1. John Semmelhack | | #1

    If it was advertised, it was probably this one:

    ...but for the money, your much better off getting this one (tip: it costs less than Sense):

  2. Trevor Lambert | | #2

    You might also want to look at Brultech Greeneye.

    The iotawatt looks to be limited to 12 channels (plus mains), and remember every unbalanced load uses up two (range, dryer, etc.). If you have just a few circuits you want to monitor, that's fine. If you want to monitor the whole house, that's not going to cut it. The Greeneye allows up to 30 channels (plus mains), and two CTs can be connected to one channel so you don't use up two channels for those unbalanced loads. If that isn't enough, you can link systems, giving you another 32 channels. The base system comes with 20 CTs, but extra ones are pretty cheap. It looks cheaper than the energycurb, and much better. The iotawatt is the cheapest by a wide margin. The one thing I don't like about the iotawatt is the cables on the CTs look pretty thick, and being terminated with a 3.5mm stereo plug means you can't cut them to length. Getting 14 of those through a conduit seems like it would be non-trivial.

  3. Andris Skulte | | #3

    Great timing - I'm deciding between the Greeneye and IoTaWatt myself...

    I like the idea of open source, especially if we can add features in the future, like identifying appliances based on signature (manually, I don't need automatic).

    You can always get a 2nd IoTaWatt, but I'm not sure if the total circuits can be summed across both of them.

    I believe on unbalanced 240V (like a dryer or range), you can run both legs through one current tap, but switch direction on one so the current polarity doesn't cancel out.

    For balanced 240V (well motor? HVAC?), you can run one CT and multiply by 2 in the software settings.

    You can also run multiple circuits through a current tap as long as you don't exceed the capacity and saturate the core.

  4. Trevor Lambert | | #4

    Yes, you can run both legs through the transformer (T in CT stands for transformer, not tap). You're limited by the physical size of the opening and the ability to route the conductors, which is not a trivial consideration if you're dealing with 10AWG or 8AWG as you would be with a dryer or range. By putting both 120V legs of a 240V split circuit through the transformer, you''re doubling the current going through it. So instead of measuring 40A or 50A and multiplying it by 240V to get the power, you're measuring 80A or 100A and multiplying it by 120V to get the power. You're basically passing the same conductor through the coil twice, albeit the load on one conductor is slightly different (the difference being returned through the neutral). Just something to remember when you're choosing your CTs.

    Balanced loads just need one CT, and in fact this is preferable. Examples for residences include water heaters, baseboards, well pumps. Some ERVs, ranges, cooktops and dryers are balanced as well, since plenty of the world has 240V residential power only. My Paykel cooktop has no neutral wire, but my (awful) GE wall oven does.

    Assuming you can combine the two iotawatts into a 26+2 channel system, the price is coming into Brultech territory anyway.

  5. Ira Broussard | | #5

    I had three ECM-1240's (precursor to the GreenEye) in my previous home. I was a fairly early adopter, so there were some pains getting them connected, working with the software, etc. Once, I got them sorted out, they worked well. Very good customer support back then, but it's been several years since I've needed support.

    I bought a GreenEye a few years ago to replace the 3 ECM-1240's as part of a major remodel about three years ago (home flooded). After the house flooded a second time a year later (hurricane Harvey), we sold the house so I never got the GreenEye installed. I still have it, and will be using it in a new home (if it ever gets started/built).

    They do provide some interesting information on electricity usage. You can see patterns of usage, etc. I think I monitored about 20 circuits. The major electricity consumers were on individual channels. Some circuits (e.g., all the circuits in the master bedroom) were combined onto single channels. The ECM-1240's were good, solid products, and the software got to a point where it was also good. I assume the GreenEye is just as good.

  6. Ryan Lewis - Zone 4A | | #6

    Maybe it was curb. I think it was something else though. the iotawatt is cool but it’s wifi only. I specifically want it to use Ethernet

  7. Patrick OSullivan | | #7

    Unfortunate to hear Sense isn't working well for you. Have you looked at your issues with them in any detail?

    I held off on Sense for a while but I'm glad I purchased it. I'm quite impressed with their product overall. One thing I tip my hat to them on is the overall responsiveness of change in load to visibility in the app. Speaking as someone who works with time series analytics, they've done a pretty good job in this regard.

  8. David Martin | | #8

    I was frustrated that Sense failed to recognize most of my major energy usage devices. Then I got a couple TP-Link HS110's. Without Sense they have an app that shows usage of whatever is plugged into it. With Sense, I plugged my entertainment system into the plug so now Sense can recognize the system and show that usage as part of my total consumption. And it was only another $16 per plug.
    My only remaining complaint about Sense is that it cannot recognize my heat pump and because the heat pump is 240v I cannot plug it into the TP-Link.

  9. vap0rtranz | | #9

    +1 to Ether over Wifi. For devices that stay physically put, I think Wifi is overkill. Consumer grade Wifi was created for ad-hoc mobility, not static comms. The industry disagrees, and so consumers follow, and now Wifi is on everything (despite the myriad of problems in the radio spectrum ... I tested interference from a microwave, neighbor's WAPs on default channels, et cetera problems that can introduce latency or packet loss, which I hope speaks for itself as concerns for anyone collecting accurate data). have several boxes with Ether on them still, and it will connect to other devices like IoTaWatt. I've not purchased one yet ... have to convince my better half of the value :) If you're up for customizing/extending, and/or connecting multiple devices using industry standards (via MQTT for example), instead of being locked into the AppleInc way of doing tech, then opensource is the way to go.

  10. Jonah Petri | | #10

    I'm an engineer with Sense, and a long time GBA lurker. I'd be happy to answer any questions you guys may have!

    1. Ryan Lewis - Zone 4A | | #11

      Jonah, is there a reason they aren’t making a wired sense? And a guided training mode (tell sense that you are turning a device on, and then off, etc), so it can learn the distinct signature of every device..?

      1. Jonah Petri | | #12

        Hey Ryan,

        For a wired version of Sense: it's a comment we've heard loud and clear. Turns out that the back corner of a basement doesn't always have the best WiFi reception! :D Thus far, the complexity of manufacturing and supporting multiple hardware products has been more than we are ready to take on, but as we grow, that may change. Stay tuned!

        As for training Sense, we get this question a lot. As it turns out, electrical devices are complex enough that the type of data we would get from a guided training mode is not useful for general recognition. We need to see devices being used in their natural usage context to give us the data we need. There's some more info on the Sense FAQ here:

        If you take the example of a simple 100W incandescent, its energy profile when it its turning on and off is largely dependent on its current temperature. A bulb which has been off for 10 minutes (the common case) will have a very different power curve than one which has been off for 30 seconds. The same is true generally of most high-wattage devices, which are the ones we really want to hit. (We're here to help homeowners save energy, after all, so we have to go after the big stuff!)

        I hope that helps a bit!

        1. Ryan Lewis - Zone 4A | | #13

          that’s somewhat surprising, but, nevertheless senses existing ML isn’t that good in my house (At this point I have zero confidence in the results). I wouldn’t mind being able to help it. In particular, again hardware, why can’t it learn individual circuits, where one can try to enumerate all devices on that circuit?

          1. Jonah Petri | | #14

            There no difference, electrically, between different circuits (on a single phase) in your house. There *is* a difference between the phases of power coming into your house, which in North America residences is typically split-phase service (two phases of power, 180° out of phase) and Sense definitely uses that information to detect devices. (Although that's no panacea, as a vacuum cleaner can certainly change phases as you plug into different outlets!)

            Is your issue mainly with your heat pump? I have a Mitsubishi Hyper Heat unit and Sense has a bad time with it as well. It's something we're working on, but I'll say that the inverter-driven motors are quite difficult, and finding good sources of ground truth for those units is also very difficult.

            Sense support is also able to manually intervene in some times of device mis-identification, and though I cannot access your house's info, if you get in touch with them and give permission, they'll be able to take a look and see if there's something which needs to be adjusted. The address is [email protected]!

  11. W Ramsay | | #15

    I began looking at this a couple of years ago and decided then that the products currently available just weren't mature enough. We moved in to a new house in June and I'd like to begin getting a handle on our electrical usage.

    To me it seems the best system would be a combination of individual circuit sensors along with signature recognition for the rest. Kind of a Sense/Curb + Greeneye/Iotawatt. You can get dead accurate info for CT'd circuits and I'd think also help the algorithmic system as it could correlate what was or was not on these definitive circuits. You could potentially move the CT's around to help w/ learning?? (@jonah petri ?).

    Interface w/ HA, HVAC, security, surveillance and other systems. In my case I'd think it could learn a lot from what our C4 system is telling stuff to do. Or at least tell me 'lighting scene Morning Coffee turned on and is using xxxkw'. Or 'Honeywell Redlink turned on HRV 1 and is using xxxkw'.

    Overall it seems there is a lot more information that Sense and others could use to know what's happening more accurately.

    Also, no mention above of Emporia Vue or Efergy? The systems I think I'm considering are:

    - Sense. Have added 2 circuit sensors. That's a start but 8 or 16 would make me happier.

    - Curb.

    - Iotawatt

    - Efergy

    - Emporia Vue


  12. C L | | #16

    The thread linked below may be helpful to you - I researched every one of the systems mentioned in your post above and included the info I found.

  13. W Ramsay | | #17

    Great info. Thanks. I wonder why that was 4 pages down on my search (I only looked at the first 3 pages because everything was old).

  14. W Ramsay | | #18

    Just to follow up on this. I ended up getting an IoTaWatt. Overall quite happy with it. I've just been using the graphs within the web interface which are rudimentary but they've done what I needed them to do.

    The one graphing bit I wish it had was an easy way to see what the $ cost is for a circuit. E.G., how much does the hot tub cost to run or the IR heaters on the porch, etc. Some third party apps provide that but I've not yet found time to set one up.

    1. Charlie Sullivan | | #19

      Yes, I got an IotaWatt too and I think it's great.

      Do you have time-of-day pricing? If not it's must a multiplication of the kWh number by the rate. I guess finding the kWh number is not all that straightforward--in Graph+, under the graph, there's a statistics tab, and kWh is the right most item. That's for the time period shown.

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