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Black & Decker EM100B Power Monitor

*Est. $50
June 2011
by ConsumerSearch
Black & Decker EM100B Power Monitor

Whole-house energy monitor

  • Inexpensive
  • Works with large appliances
  • Works with wall switches
  • Tracks entire usage
  • Cordless indoor display
  • Doesn't work with all utility company meters
  • Can't read differences less than 100 watts
  • Can be tricky to install
  • Some reports of wireless issues
Where to Buy

The Black & Decker EM100B Energy Saver Series Power Monitor is a whole-house electricity monitor that sends data wirelessly from a sensor mounted on your utility company's meter to a cordless display you can read indoors. It's designed to track home electricity usage on a real-time basis (updated every 30 seconds), plus accumulated usage (over an hour, a day or any time period), and estimated monthly usage. This makes it easy to estimate your power bill and get immediate feedback on any changes you make. A button on the display also lets you isolate the usage from a single appliance.

Setup requires only a screwdriver for mounting the sensor, plus entering details into the display about your local electricity rates. You can enter even complex tiered rates. Reviewers agree that once setup is completed, the device is very easy to use; actual installation ease gets more mixed reviews. Some owners say it's fast and easy as long as you read the instructions, while others say it's complicated and finicky.

There are a few caveats. A few power companies don't allow a sensor to be mounted on the meter. If permitted, the sensor works with approximately 90 percent of all home power meters -- but not all. The maximum range between meter and the indoor LCD display is 60 feet -- but that's under ideal conditions, through a single wall. The projected bill probably won't match your actual bill exactly, because of date differences (especially with tiered rates).

We found some complaints about phone support for this product, but the manufacturer's support website does offer detailed guidance and troubleshooting. The warranty is for two years. Blue Line Innovations manufactures the Black & Decker monitor under license, but its self-branded and pricier BLI-28000 Power Cost Monitor (*Est. $110) has a longer wireless range. If you want to monitor just one or two appliances, or monitor low-wattage devices (the EM100B can't read differences smaller than 100 watts), the Belkin Conserve Insight F7C005q Energy-Use Monitor (*Est. $30) might be a better alternative. Though it will only keep an eye on one appliance at a time, it's easy to install and use.

We found expert reviews covering the Black & Decker EM100B energy monitor at, a technology site affiliated with The Wall Street Journal, as well as at Wired and the Prism blog from Reuters. We also found over 100 reviews at In addition, several detailed single-product reviews show ample detail about the Black & Decker monitor -- with useful summaries of its pros and cons.

Blue Line Innovations BLI 28000 PowerCost Monitor
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New: $109.00 $69.99   
In Stock.
Average Customer Review:  
Belkin Conserve Insight Energy-Use Monitor
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New: $29.99   
Average Customer Review:  
Where To Buy
Black & Decker EM100B Energy Saver Series Power Monitor

 (195 reviews)
Buy new: $99.99   2 New from $79.99

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Our Sources


This review favors the Black & Decker EM100B Power Monitor after comparing it with two other whole-house energy monitors. The Black & Decker monitor is the least expensive and is judged simple to install and use.

Review: Geoffrey A. Fowler, Gadgets Show How Much Power Your House Eats, July 8, 2009

2. Wired

This review notes that the Black & Decker monitor is easy to use once set up -- and tracks usage and isolates appliance usage well -- but is skeptical about whether or not users can really cut electricity bills by as much as 20 percent. Thus, the payback period (based upon the price of *Est. $100 at the time of the review) looks long. The other main drawback is that initial setup can be finicky.

Review: Black & Decker Electricity Monitor Sleights the Power, Rachel Cericola, Sept. 29, 2008

3. Reuters praises the Black & Decker Power Monitor as easy to install and use, but notes that it doesn't work with all utility company meters and that the wireless range is limited. No actual testing is documented.

Review: 4 Ways Electricity Monitors Can Trim Your Energy Bills, Editors of, March 22, 2011


Over 100 users review the Black & Decker EM100B Power Monitor at this retail site, with about 80 percent seeming to be reasonably satisfied with it. Most say it's easy to install. Owners like the way you can see the cost difference a specific change makes, and that you can zero out background usage to focus on a dryer or other large appliance -- but note that it doesn't measure low-wattage devices (for which you need a plug-in outlet monitor). Some owners complain that it's not compatible with their meter (or permitted by their utility company). Black & Decker customer support isn't a strong point.

Review: Black & Decker EM100B Energy Saver Series Power Monitor, Contributors to


This enthusiastic single-product review, based on the author's use in his own home, notes that setup can be quite fast: including reading instructions, about five minutes to install the sensor plus another five to set up the display. Feedback is quite useful, both for whole-house usage and for finding out how much specific devices and appliances use. No drawbacks are noted.

Review: Black and Decker Power Monitor, Rich McComas


This review rates the Black & Decker Power Monitor a 7 (on a 10-point scale) for value -- noting that even at a retail price of $100, the monitor can pay for itself in savings. The rating for performance is just 5, because the device isn't intuitive to use -- reading the instructions is a must -- and the monitor isn't compatible with or permitted on all utility company meters.

Review: Black & Decker EM100B Energy Saver Series Power Monitor Review, Thomas Gaige, Feb. 26, 2010


This detailed, well-illustrated review provides plenty of detail about the Black & Decker EM100B, recommending it as quite useful but noting that it won't predict an exact month's bill. Nearly two dozen readers add comments; most are enthusiastic, but one notes that his power company not only removed the monitor from his meter, but charged him nearly $200 extra as a removal fee.

Review: Black & Decker Power Monitor Review, "Julie", Nov. 21, 2008


This detailed review notes that while installation and setup are easy, they can be time-consuming if your utility company charges a tiered rate. The only other drawback noted for the Black & Decker EM100B is the relatively high price (*Est. $100) -- but it has become easy to find this monitor for much less since this review was written.

Review: Black and Decker Power Monitor, Kristofer Brozio, Nov. 16, 2008

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