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My First Four Months With an Energy Monitor

By Futli @futlim

I’ve been testing Powerhouse Dynamics’ eMonitor energy monitoring system for a few months now. And since living with an energy monitor is a new thing, I have periodically recorded my thoughts about it. Some of this has also appeared in a review in the October 2010 issue of Electronic House.

If you’re unfamiliar with the eMonitor, it is a circuit-level electricity monitor that can also monitor solar production-though I don’t yet have a PV system, so that’s not included here. The system costs about 0 for 24-circuit monitoring and a two-year subscription of 9. The interface appears over a web-based computer interface and a new iPhone app.

Boiler Engineer

This should give you a good indication of how one household has used his eMonitor for about four months now, through hot weather and now cold.

Set Up

The eMonitor arrived on time. I took it out of the box and possibly for the first time ever, I read the entire user manual. Then I called my electrician, because installing it requires removing the front panel of our electrical panel, and that’s where an amateur like me stops.

My electrician has never seen an energy monitor system before, but he seems to know what to do. He removes the front panel of the electrical service and gets to work.

The eMonitor measures electricity usage via current transformers (CTs) that clamp around the two electric “mains” and up to 24 circuit wires. These sensors measure the electromagnetic field created by electricity use, and are fairly accurate. The CTs connect to a processor mounted near your main circuit panel and then attach via Ethernet to a network router and home network. That enables Powerhouse Dynamics to see the measurements and include them in the computer interface.

But first the CTs. The electrician placed the doughnut-shaped clamps loosely around the mains and the circuits. Dang, I thought. I could have done that! The wires from the CTs must go into the brick-size eMonitor processor that is mounted near the electrical panel. And while the electrician does this, he fills out a form so we know which circuits are on which ports of the eMonitor processor-as well as their amperage. Later, I input this information into the web-based registration and set-up portal so Powerhouse Dynamics knows what circuits are what.

The electrician would have liked numbers on each CT for easier marking, and a processor capable of handling more circuits. (I had to leave out two bedrooms, and my house isn’t quite 3,000 square feet.)

The electrician’s work took about an hour or so, and my work at the registration site about the same. But I expected it to be far more complicated. The only hitches were figuring what times to input, to receive alerts if things like the well pump, boiler, and fridges are on for too long or not at all. The alerts are a big part of the eMonitor’s appeal. And I am pleasantly surprised that we’re soon up and running. Then I just needed some results, and that doesn’t take long. After all, I’ve got a teen and a tween. Those dudes are always leaving stuff on!

Day one (and a half)

The web-based interface is cool and intuitive-as well as colorful. The front page of the secure site shows my home’s current electricity usage in watts (updated every minute), the circuits and appliances currently drawing the most power, the top energy users in our house over the last few days, our monthly electricity costs to date (you input your utility’s rates during the registration), and a pie chart representation of our top electricity users. There’s also a carbon footprint comparison-ours is still smaller than our state’s average-heh, heh-and a graph of our electricity consumption over the past two days.

You can dig deeper and see a color-coded graph of hour-by-hour or minute-by-minute usage of all your circuits, which are color-coded. You can even highlight a section to get more granular. I love this feature.

You can also go to a Circuits page to examine individual circuits as well, and some of these come with energy-saving suggestions, such as reminders to clean the lint filter in our electric dryer.

But what I love most is that the interface does not appear as something designed by engineers for engineers. It’s easy for any homeowner to grasp.

Week one

The coffee maker uses almost 900 watts when it’s brewing!!? And what’s this 1,100 watts in the rear bedroom and bath and another 1,200 in the kitchen plugs at 6:24 am?

Come to find out, the 1,200 watts on the kitchen plugs is a toaster/convection oven, and the 1,100 watts in the bath is a hair dryer. Who would have thought?

Also, I’m a bit surprised to find that my two biggest energy hogs are the subpanel in the garage and the “cellar and smokes.” It’s easy to deduce why, though. We had been been running an old dehumidifier in the basement, because-guess what?-the new Energy Star-rated one we bought broke down after a year of use. They just don’t make things like they used to. But we should really invest in a new one. And in the garage we have an 18-year-old refrigerator, which was once considered energy-efficient. Just goes to show how much more efficient appliances are now, considering our new fridge is about twice the size as the old one and uses less power.

Such are the travails of a homeowner with an energy monitor. Because the eMonitor measures a home’s electricity use at the circuit level, major appliances like the refrigerator, electric clothes dryer, electric stovetop and oven are easily measured and identifiable. Other circuits, like “rear bedroom and bath” and “kitchen plugs” require a bit of detective work.

I now have no desire to measure my total home’s energy use only, as some other inexpensive energy monitors do.

Week Two-The Geek Out

In my two weeks with an eMonitor, I’ve also uncovered the cycle times of our two refrigerators. I’ve found that the old fridge in the garage uses about 50 watts more when cycling on than the new one in the kitchen, an aging dehumidifier in the basement uses 800 watts when on, and our old electric dryer uses more than 5,000 watts when on (yikes!).

Since getting the eMonitor, I occasionally get geeked out while examining our electricity use and seeing where we can save.

My only complaints include the color-coded circuits graph showing energy usage in watt hours (watts divided by hours of usage), while the more detailed circuit-level graphs shows usage in watts. This was initially confusing, and I thought something was wrong with the interface. (Though the watt hours have come in handy when calculating the Energy Factor of my older appliances, to compare with newer Energy Star-certified models.)

Also, as part of a subscription to its service, Powerhouse Dynamics sends alerts when circuits appear to be off or using abnormal amounts of energy. I keep getting alerts for my boiler and well pump being off, though while registering I made sure to give ample time for these to be “off.” I love the idea of alerting homeowners to appliances like water heaters that are using too much energy and may be about to fail, but the alert system appears to require finessing. (Powerhouse Dynamics has since fixed this issue, and now I rarely get alerts.)

From the early results of my eMonitor, it looks like my family should look into:

  • A more efficient electric clothes dryer.
  • A more energy-efficient dishwasher.
  • A new, Energy Star-certified dehumidifier.
  • More dimmable lights, CFLs and LED lamps.
  • Further reducing unnecessary standby/vampire loads

I am so proud of ourselves. We’re already doing pretty well as a family on our electricity use. And now, maybe, we can do better.

Week Two and a Half

I’m worried of an opposite effect from the eMonitor-that it’s making me not run the dehumidifier as much, and that could lead to more moisture in the basement, mold and mildew, just to save some energy. I am more conscious now about shutting the dehumidifier off.

I’ve been running that old dehumidifier at a lower setting, hoping it will automatically turn on and off and keep the basement fairly dry. I keep meaning to check how often it cycles via the eMonitor, but I’m incredibly busy with a deadline and keep forgetting. Plus, I know once I’m on the eMonitor page, I’ll get obsessive and be there a while. So I forget.

I receive an alert that my eMonitor is offline. Must be our bleeping network router, which requires the occasional reboot. I unplug it and plug it back in, check the eMonitor and the computer interface, and we’re back in business.

Week Three

I haven’t checked the eMonitor in a while. Have I reached the two-week plateau where energy efficiency experts say people get bored with their energy monitors and stick them in a drawer, hardly ever to be checked again? Is this my figurative eMonitor drawer?

Some Time Later

I’ve got to check that eMonitor. We’ve been running the dehumidifier and bedroom fans during a late summer heat wave. And I’m curious to see those dehumidifier cycles. I wonder what our carbon footprint is now. It will kill me if it’s bigger than the state average.

A Couple of Months Later

I see that while I wasn’t checking my eMonitor, Powerhouse Dynamics added widgets for Phantom Power and a Solar Checker (“Is Solar Right for Me?”). The eMonitor says we are wasting about per month in phantom power, mostly in the living room where a cable box and TiVo are on 24/7 and sucking more than 70 watts. Something must be done about that.

The solar checker gives you an estimated cost and system size, based on your location and electricity usage, to generate a certain amount of electricity, which you can adjust with a slider. To produce 100 percent of the power for my house would require about a 5-kw PV system and cost me about ,000-after K in incentives. Tempting, though solar thermal may still be a better bet for me.

And About Now

Yikes! I’ve been running an electric heater at times in my office, and that comparative carbon footprint on the eMonitor home page is almost as big as the state average. That doesn’t sit well with me, but the alternative is burning more oil for heat-and knowing the mix of nuclear, wind and gas power (with very little coal) we receive from our municipal utility, I’d rather use electricity to warm my tootsies occasionally.

I have also recently noticed a weather tab that shows my overall energy use during the day as it correlates to the weather. You can also see this by week and by month. We do run some electric heaters at times, but this would be more useful if we heated our entire house with electricity or were producing solar electricity. There’s also an app to integrate a RainWise weather station with my eMonitor, to see the relationship even better. Maybe some other time.

I like a new bar on the home page that shows my projected electricity costs this month. It’s an estimate based on my average utility rate, but useful nonetheless and addresses one thing I found lacking about the eMonitor interface.

I also just downloaded the new free iPhone app for the eMonitor. It gives you a quickie look at what electricity your house is using now, the top circuits using electricity, and how many watts they’re using-as well as overall usage that day, week and month-and costs in the last month per circuit. It’s a pretty basic rendition of the web-based interface, and could be helpful to check while you’re on the road or when the kids come home and fire up the Xbox instead of doing their homework. The app also updated my current energy use in a timely fashion-as eMonitor updates about every minute. My iPhone app was a bit behind the web site, by that’s no biggie.


As you can tell from how often these updates were made, I don’t look at the eMonitor interface nearly as much as I did in the first few weeks. That’s to be expected, though. At first you make whatever changes in your house to your electricity use that you can, then you tend to forget about it. But it’s still very useful to go in once week, even once a month and glance at your electricity use. Those dollars being wasted on phantom power make me want to do something more to save electricity in our entertainment system, though I still don’t know if I want to shut off a cable box and TiVo that take so long to reboot-even if I power them down in the middle of the night. And the cost of running 1,500-watt electric heaters in the chilly months encourages me to look into better insulation. Or solar thermal so we might free ourselves from heating with oil.

I also like how Powerhouse Dynamics keeps adding to the web interface with new widgets and apps. Eventually, most of this energy monitoring and energy management will be automated and invisible, running behind the scenes and only shooting us alerts when we need them. So I don’t feel too bad about not checking on it as much. It is still very useful to have. It’s making me really think about ways to save electricity. And it should prove even more helpful as energy management moves forward and matures.

My First Four Months With an Energy Monitor

Steven Castle is a green tech journalist and co-founder of GreenTech Advocates, (http://GreenTechAdvocates.com) an informational resource for businesses selling green home technologies and businesses going green.

Copyright © 2009 GreenTech Advocates. All Rights Reserved Worldwide.

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