Archive for the 'Energy Monitors' Category

Our new energy monitor

Photo of eGauge installed

The setup

As you can see in the photo above, we have 2 new eGauges. Each monitors up to 12 circuits, for a total of 24. When you count 2 lines in, solar and several circuits that have double breakers pulling unbalanced loads, that ends up covering 20 individual things we can now monitor. We were previously monitoring only 7 circuits plus solar and power from the utility.

We’re now monitoring the kitchen refrigerator, basement freezer, ventilator, ventilator pre-heat, barn, the backup electric resistance units in the bedrooms and living room, and a bunch of other circuits including the one we charge our plug-in hybrid.

We chose the EG3000 model without the HomePlug AV. Our router is very near the electric panel in the basement so it was easy to wire it directly using ethernet cables. The ethernet model requires a separate enclosure. You can’t put it in the panel box. This is fine because there is isn’t much room in the panel box, especially after you install 24 CTs and a load of twisted spaghetti wire (see above). My electrician installed this small box next to the panel with all the wires running through conduits. I’m going to cut a piece of clear plexi to fit over the box so you can still see everything inside, but keep the dust out.

The install

The eGauge install was fairly similar to the eMonitor. You need to power the monitor devices directly from the breakers in the panel box, and you need to keep track of which lines you are monitoring. My electrician figured it quite easily, although he installed all the current transformers (CTs) in the opposite direction. Thankfully this doesn’t really matter as long as you are consistent in the direction you install them.

The cost

The 2 eGauge units plus the CTs and shipping worked out to $1,282. Our electrician charged us about $400 for the physical install. I did the configuration and spent several hours messing with the settings to get everything working correctly. The documentation is not great, but I figured most of it out. Having some prior experience with an energy monitor (we’re now on our third) definitely helped.

I don’t remember how much we paid for the eMonitor 2 years ago. I seem to recall in the $600 range for the 12 circuit wifi model, plus another $400 for install. It looks like you can now get a 24 circuit ethernet connected model for $700 plus the 2 year subscription fee, which for us was about $180.

So why did we switch?

1. No yearly licensing cost

I absolutely enjoyed the data that came out of our eMonitor (see our post 2 years ago), but I deplored their architecture and business model which required me to pay a subscription fee every two years to have access to my data on their servers.

eGauge has no licensing fees and stores its data right on the box, at 1 minutes resolution for the first year and 15 minute resolution after that up to 30 years.

2. Data quality

I’ve been tinkering with some new analysis techniques that required minute resolution data. So I downloaded 2 years worth of minute data from my eMonitor. This was not a pleasant experience since they only allow you to download 2 weeks of data at a time, the data files are large. Then I proceeded to look at the data and try to recreate the hourly data from the minute data. This should be an easy exercise, but I found that there were lots of little gaps in the data. I was not able to fully recreate the hourly data I had originally downloaded. After numerous emails with their service desk, they stopped responding.  I don’t think they could explain the gaps. I don’t know if the problem was hardware, or data was lost in translation, but it didn’t give me a lot of confidence in the device or service.

I spoke about this issue with a few people at the Better Building by Design conference in Burlington, VT back in February. The Efficiency Vermont booth was demonstrating some energy monitoring case studies and had good things to say about the eGauge. I have a huge amount of respect for the Efficiency Vermont organization. Lots of smart folks there.

3. Make-ability

I enjoy building stuff and tinkering with different ways of analyzing and visualizing our energy usage.

With the eMonitor, I downloaded our data from their servers once a month. It wasn’t easy enough to do in any shorter increments and I wasn’t going to apply for a developer license to access their databases directly.

Since the eGauge data is on the box in my basement*, I can access realtime data through the built in web interface or through a simple API. This is awesome for makers. I’m looking forward to building a new realtime interface to view our energy data.

*Since the data is on the box in my basement, I’m setting up an automatic backup.

4. Customizable

the eMonitor may be different now, but when I bought it 2 years ago, it came as a kit to monitor several different sized loads. We ended up not using one of the monitoring slots because we didn’t have a circuit I wanted to measure that matched the monitor amperage.

eGauge lets you mix and match components. I picked the number and size of the CTs and the type of monitor configuration to match my setup.

Screenshot eGauge 6hr view

That’s it, go out there and measure stuff.

Cruise control for the home

Drivers and pilots make use of technologies that make their life easier and increase energy savings, why not home owners?

I’ve been thinking a bit lately about the future of energy monitoring and intelligent control systems. We recently installed an energy monitoring system from Powerhouse Dynamics. It is very good at telling us how much energy we’re using for which circuits, and advice about how we can use the appliances on those circuits more efficiently. Although we don’t own one*, Nest has been in the news a lot lately for their intelligent use of occupant behavior history and weather predictions to actively optimize your heating/cooling equipment, and for telling you how much you saved by using their product.

I’m imagining an energy monitor that tracks our energy usage for major appliances and through a combination of active control or user suggestion determines the ideal time to use those appliance to 1) optimize their effectiveness, 2) increase our enjoyment of said appliances and 3) lower our energy usage.

Example 1. Water heater. Nest says the thermostat controls 50% of your home energy usage. For us it’s the water heater because our heating and cooling requirements are so low. Now that Martin Holladay has determined that tankless water heaters are a waste of money, we should be able to make tank style heaters more efficient. Let’s say our monitor knows generally when and how much we tend to use hot water. Similar to the calculations required to heat and cool the house, it could determine the optimal water temperature between 120 or 140 degrees F and when the heat is required. For us, it is mainly needed in the morning when we take showers and a bit in the evening when we do a bit of hand washing of pots and pans that don’t fit in the dish washer. No need to stay at 120 or 140 degrees F 24/7/365.

Example 2. Clothes washer and dryer. Let’s say our monitor energy tracks how often we wash clothes and dry them. Let’s say it understands some correlation between season, outdoor temperature and humidity. It might suggest after a few months of usage and weather data that if we wash our clothes this Sunday rather than Saturday then we can dry them on the drying line versus having to use the dryer because there is a higher chance of rain on Saturday. Or maybe it knows we don’t have a drying line but we have a solar array that can supply the required energy without going to the grid. It could predict the energy savings if we follow the monitor’s advice.

Where to control these appliances? At the circuit box or at the device? Circuit level control seems crude. It seems like it would make more sense to have more intelligent devices, each knowing what factors affect it’s efficiency. But then you end up with lots of appliances with redundant functionality. Plus, you may be missing out on efficiencies across appliances.

Consider if we decide to wash and dry our clothes in the winter when the sun is shining and powering our solar PV system while adding passive heat via our high solar gain windows that face south? Maybe we can lower the set point on the heating thermostat so that we don’t overheat. Or maybe we use the condensing dryer to heat the house instead of the air-source heat pump.

This is one of the scenarios that makes me think that someone is working on a Nest-like appliance for the entire home. It will monitor not only energy and hot water usage, but also every generation, occupant behavior and weather predictions to put the house on auto pilot, or suggestion or cruise control mode. Occupants can override this mode manually whenever required and then compare at the end of each month to see who did better, them or the algorithm. Who knows, maybe the user gets a credit on the system if they out perform the algorithm more than 3 consecutive months.

None of these ideas are new, and I’m guessing most are already being used in large scale commercial operations. But I think the Nest shows us that the future is closer than we think for home owners. We don’t need a lot of intelligent appliances, or a lot of intelligent appliances talking to each other. We don’t even need automated controls, but a simple auto pilot for the home can maximize the efficiency of home appliances and the happiness of the home owner.

* Note to Nest. We don’t currently own a Nest thermostat because our heating and cooling loads are so low, but we would gladly own one if it could use similar logic to control our water heater.

Our new wireless energy monitor

We were excited to see our new eMonitor 4 from Powerhouse Dynamics arrive Wednesday. We purchased it through EnergyCircle. Sage, the rep at EnergyCircle, said it would ship first thing in the week and he wasn’t kidding. For more info see our previous post, Power monitoring – lessons learned.

The installation was very easy. The setup had a few kinks.

First the install.

The documentation for the eMonitor is very good at a hefty 41 pages. We bought the 14 circuit model with includes 14 sensors (called Current Transformers or CTs). 14 sounds like a lot, but two of those sensors are for the two mains coming into the panel. If you have 200 amp service, which is fairly standard, you have 2 lines carrying 100 amps each. Now you’re left with 12 sensors.

That still sounds like a lot, but most heavy use appliances use double breakers or 240V. Some of these appliances use power evenly across both circuits which means you only need to monitor one of the circuits. Examples seem to vary, but for us that includes the hot water heater, water pump and clothes dryer. If the appliance can use power unevenly across the two circuits or you’re not sure if it uses balanced power, then you need to monitor both circuits for an accurate reading.

And for the final complication, six sensors are for 50 amp circuits and the other six are for 20 amp circuits. Which means, 12 sensors doesn’t get you far. For us, we can only realistically track eight things:

  1. Solar generation (1-50A sensor)
  2. Hot water heater (1-50A sensor)
  3. Air source heat pump (2-20A sensors)
  4. Well pump (1-20A sensor)
  5. Dryer (1-20A sensor) Probably should have used 2 but then we wouldn’t have been able to track the washer or dishwasher.
  6. Washer (1-20A sensor)
  7. Dishwasher (1-20A CT)
  8. Range (2-50A sensors)

See what we mean? 14 total sensors, 8 things to track. If you count it up, you’ll see we have an extra set of 50 amp sensors left over. We don’t have anything else in the 50 amp range to monitor. So we can’t even make use of everything that comes in the package. Sage tried gently to steer us toward the 24 circuit model, but we felt like we were already spending more than we had budgeted. Would the extra circuits be nice? Yes. Do we really need to track plug loads and lighting circuits? No.

The base unit connects to all the sensors and fits inside your panel box. Ours was a bit of a squeeze. It draws its power from one of the breakers, so you will need a free breaker slot to power the unit. The base unit transmits data to the gateway via radio signals, and from the gateway to the wireless router via WiFi.

This part of the installation was incredibly easy. I was pleasantly surprised. The gateway initially sets itself up as a wifi network, so all we had to do was connect to the gateway’s wifi network, use our browser to pull up the configuration page on the gateway IP address and enter our wireless router connection info.

One thing to note about the install. If you really want to connect the gateway to your router via ethernet and not use the wireless feature, you can. You just need to make sure your dealer knows that so they can pre-setup the gateway to work with an ethernet connection. From the documentation, it appears that you can also change this later with a software download.

The kinks.

So far so good, but then the problems started. This is a new product and you have to expect a few kinks. Version 4 now separates the product purchase from the service license purchase, so we had to go to the Powerhouse Dynamics site and purchase a license to operate the product. When I tried to use the online registration process it wouldn’t let me complete the process. To add insult to injury, there was no email or phone number on the site. Thankfully, Sage pointed us directly to the Powerhouse Dynamics CEO Martin and master support guy Ben.

As it turned out, the license purchasing part of their site doesn’t work with Safari. Not a big problem. Last I checked Safari has about 5% of the desktop marketshare, but over 60% of the mobile/tablet market. This is 2012 and there is no good reason not to test and support your consumer product for Mac or iPad users, particularly for a premium product like eMonitor. We simply had to switch to Firefox and the registration process was completed.

Next problem was that our unit’s serial number had been mislabeled. Someone else out there has our number, we got theirs. This took a bit of back and forth but Ben set us straight with the correct serial number and we made it past this second hurdle.

The rest of the setup went fine until we got to the calibration step. If you are monitoring solar generation, then the system needs to determine the direction of the power inputs. They have a nice wizard to lead you through the process. It involved turning off the solar switch, running the calibration, then switching the solar back on and running the calibration again. As the eMonitor knowledge base article describes, it is a fairly complex thing to determine. In the end, we realized we had placed the main feed monitors downstream of the solar tie-ins, confusing the calibration. Ben once again came to the rescue and fixed everything from his end after I moved the sensors.

Everything appears to be working now.

The Dashboard, exporting data and mobile support

The eMonitor dashboard does not appear to work on the iPad. There is no app for the iPad and it doesn’t work in Safari.  I logged in and got a blank page. The iPhone app is good, but it doesn’t break out unmonitored power. It also doesn’t change with the orientation of the phone to display more data or real-estate for the charts which are very static. You can’t zoom or change the parameters being charted.

On the desktop I find the energy dashboard navigation, page layout, and charting a bit clunky and old, but I’m an interface designer, so I expect a bit more from my apps, especially when I pay $280 dollars just for online access to my data. The charts in particular are quite small. I also would like to see the energy monitor website login remember my username, and offer me the option to keep me logged in for some period of time like most browser-based email applications. It’s annoying to have to keep logging in throughout the day.

As a final note, the export function could be a bit better. The export includes columns for 44 sensors even if you only have the 14 channel model. And the downloaded file contains an .XLS extension even though it is an CSV (comma delimited) file. CSV would be perfectly fine for both Excel and lots of other applications that read comma delimited data. I’m also not looking forward to having to download this data manually. Our TED made it easy to get historical data directly from the gateway. I’m not sure if eMonitor works the same way.

My next task is to figure out how to download data directly from the gateway and display the data in my own spreadsheets and charts which look much better and allow me to include my HOBO sensor temperature data.

Our thanks to Sage at EnergyCircle and Ben at Powerhouse Dynamics for helping us through the kinks. It’s really wonderful to see the breakdown by appliance, particularly the ASHP, water heater and well pump. More fun with charts at the end of the month.

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.


– 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.


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.

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