Power monitoring – lessons learned

In January we purchased a TED5000 (The Energy Detective, 5000 series) to more accurately monitor our power usage and generation over the year. We had some intermittent problems getting it to work dependably. Eventually we were able to get it stabilized after adding an inline noise filter. Noise in this case is signal noise which can be caused by any electrical gadget plugged into a socket. All seemed well for a while and we got a great month’s worth of data for February. Then strangely TED stopped working shortly after exporting the February data, and we didn’t notice it till yesterday. Now we’ve lost 7 days of data and it still isn’t working.

We’ve found that there are two major obstacles to using TED.

1) The data transfer takes place over your power lines themselves, which is great if your router is not near your panel box. Not great if you have any appliances or products that generate ‘noise’ on the power line. This interferes with connection between the MTUs (the actual monitoring units) and the gateway. The difficulty is that it can appear to work fine for some periods, then just stop working if you plug something into the same circuit as the TED Gateway, or just something unknown happens in our case. We didn’t plug anything into the same circuit as the gateway.

2) The load profiler works great if you have appliances that have a distinctive energy signature, like a furness kicking on, but is impossible as far as I can tell for things that use a variable amount of power, like Air Source Heat Pumps, the main thing I wanted to track.

After some additional research and consultation with Walter Thomas, a PhD student studying multiple net zero houses across the northeast (including ours), I’ve decided to switch to the eMonitor from Powerhouse Dynamics. It is more expensive, but should give us more dependable data collection since it doesn’t transmit data over the power lines, and direct monitoring data for individual circuits, up to 14 circuits in the base model. (Note, this is the newer eMonitor4 model which is just now beginning to ship this month. See EnergyCircle for more information.)

The main reason we initially went with TED over the eMonitor was cost, access to data, and proximity of router to the panel box.

Cost

- We purchased the TED5002-G which allows the monitoring of solar input. It is currently $279.95 online, plus an inline filter for $9, for a total of $288.95.

- The eMonitor4-14 hardware is $499 plus a 2 year mandatory software license which in our case is $173 for the 14 circuits plus $108 for the renewable monitoring option works out to $780.

Access to data

- TED has all the data and the monitoring software built into the gateway. When you want to check or download data it is directly from the gateway. Simple, no bells and whistles.

- eMonitor requires a minimum 2 year software license agreement. From what I understand, you can download data from the gateway directly, but to view charts, set thresholds and alerts, you must login to their monitoring site. Personally I don’t need the extra functionality, I’d be very happy with just the gateway and download my own data. I really don’t like having to buy access to my data. Now that I think about it, they should be paying me for access to my data which they are surely aggregating across thousands of households and selling what they learn to other companies. My credit card company pays me in points to use my card which in turn gives them access to my purchase history. I would expect the same of the eMonitor which will now have access to my power history.

Proximity to router

- This was one of the big reasons we went with TED. Since TED transmits data over your power lines, the gateway can be plugged in next to your router which can theoretically be located anywhere in the house. In practice, this is not as easy as it sounds. To reduce problems with noise on the line, you are asked to plug the gateway into the same circuit that is powering the MTUs. And you don’t really want to plug a wireless router onto the same circuit because that adds more noise to the line.

- The old eMonitor required the gateway to be in close proximity to the router. The new eMonitor4 features wireless access, so this problem goes away. Although you must have a wireless router in your home.

Summary

After using TED for a month I realize there is another important aspect to making a decision on a power monitor, reliable up time. The primary reason we’re switching to eMonitor is that we need dependable data collection. We can’t have it going down for periods of time. Secondly, it will allow us to accurately monitor the heat pump power usage in addition to several other circuits. We’ll post more thoughts after we receive and install the new eMonitor4.

I still think TED has lot going for it. The price is right. Access to data is good. It would be great if they offered a version of the product that plugged the MTUs directly into the gateway, or a wireless version like eMonitor. For the casual home user, it’s probably not a problem if the monitor goes down occasionally.

We’ll let you know how the return process goes with The Energy Detective. Hopefully that won’t require a lot of my energy.

4 Responses to “Power monitoring – lessons learned”


  1. 1 Dan Gibson 7-March-2012 at 5:20 pm

    Very interesting and good information that can’t be learned before buying. Thank you for sharing it. I too want to segment my electric use, so I have a rough idea where all the power goes. I installed 8 subpanels with rebuilt electric house meters. It seemed expensive but I wanted monthly data and high dependability. Cost for the 8 meters and 8 subpanels was $664 ((28+55)*8). Not fancy, but simple and very reliable. I will use the TED or other for more detailed analysis when the time comes. Cheers, Dan

  2. 2 Paul Chen 3-May-2012 at 10:39 am

    I am considering getting a power monitoring device for my house, and also read that TED’s powerline communication can be problematic. I can see the advantage of the eMonitor being that the data storage is remote, so you don’t have to have a computer at home to store the data. But I think this can be overcome by having a non-volatile memory port on the monitor. Memory is not very expensive these days. If they can offer free service option and find another way to make money off your data, then the consumer can choose to “sell” their data or not. I thought about making my own power monitor, but I suspect the cost will be equal or more than buying one, and definitely will take a lot of time to make it work right.

    • 3 Larry 4-May-2012 at 9:35 am

      Hi Paul,

      There are lot’s of sensor type projects on Kickstarter that are getting close to providing much of the functionality needed for home energy monitoring. It’s only a matter of time before something better is available that does as you describe. eMonitor’s closed system is a bad business model, but it is a very reliable device. I look forward to a device with an open, well documented, API that allows a small ecosystem of app developers and device makers to use data from multiple sensing devices in the home. That time is not far away.

      Larry


  1. 1 Our new wireless energy monitor « Up Hill House Trackback on 16-March-2012 at 11:20 am

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