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Whole House Power Monitor

September 19th, 2009 Leave a comment Go to comments
This entry is part 2 of 9 in the series Generator

Review of Black & Decker Power Monitor

Black & Decker Power Monitor (Display Unit)

Black & Decker Power Monitor (Display Unit)

If you are thinking about (or already have) a whole house generator, one of the things you want to know is how much power various things in your house use. So, to properly size the generator you’ll need you will want to monitor the usage of various critical appliances and circuits. But how?

There are really three ways: hire a pro, measure individual appliances and circuits, or buy a whole-house monitor. Prior to my generator installation I used the single curcuit method (with a clamp-on multi/ammeter and a plug I built myself). But now, thanks to a great 2009 Father’s Day gift, I have an always-on meter to do the whole house load for me.

Meter Background

There are really two types of homeowner meters for sale: inductive and optical. Both do the same job, thought I haven’t seen any accuracy comparisons between the two technologies. As always, each technology has it’s advantages and disadvantages.

Inductive Meters

Inductive meters consist of a sending unit that reads the current drawn through your circuit panel via inductive clamps. The most common version of this type of meter is the TED (The Energy Detective). These types of meters have several advantages over the optical kind. Mainly, inductive meters can measure a single circuit, a single sub-panel, or the whole house and, they work while the generator is running. They’re also installed inside the circuit panel and protected from teh elements. The TED also has interesting features, like holding the daily peak usage in memory so you can really see what the peak loads were over a span of time to size your generator correctly. One drawback is that you must open up your circuit panel to install this type of device, which scares a lot of people.

Optical Meters

Sending Unit Attached to Meter

Sending Unit Attached to Meter

Optical meters have a sensor that attaches to your mechanical electric meter (on the outside, no need to open it). This sensor tracks the movement of the spinning wheel inside most electric meters and calculates usage based on that. The primary advantage of this type of system is that you don’t need to open your panel to install it, and they tend to be less expensive than inductive sensors. The disadvantage is that they can only measure the whole house, and they only work on utility power. So when the generator is running you wont have a real-time readout. They also have a sending unit installed outside in the elements on the electric meter and there is a real concern that a $100 device just won’t hold up. In fact, mine came out of the box with a leaky sending unit and I needed a warranty replacement from Black & Decker.

The Black & Decker power meter is really a re-branded meter from a company called Blue Line Innovations (http://www.bluelineinnovations.com/) and sold through various retailers. In fact, it’s an older model, because Blue Line apparently released a new version in May 2009 that adds a daily peak usage memory that mine doesn’t have. So the Blue Line site is a good place for information about the meter — better than the Black & Decker site. But nonetheless, it gets the job done for just over $100 from Amazon.com.


Rating: ★★★★☆ 

Setup wasn’t that hard. The manual is very thorough and it walks you through the calibration without too much fuss. Installing the sending unit wasn’t that hard either, though this can vary depending on meter type. In my case (a 30 year-old meter) it was as simple as tightening a large hose clamp around the meter glass and aligning the sensor arm.

You will need an electric bill because the meter calculates cost based on power used and it therefore needs to know cost information. This shouldn’t be too hard to find on most bills. There are four or five steps needed to calibrate the meter depending on how your electric rates work. But once done the receiver can give you an idea of how much your use costs. It even has a function that will predict your monthly cost depending on the usage patterns it has tracked.


Rating: ★☆☆☆☆ 

Once I got mine installed and calibrated, it seemed to perform fine. The receiver captured and held a signal about 30 feet away, through several walls. But even with a really old meter, which tends to get fogged a bit during high humidity, the sensor keeps reading the values and gives me a realistic (I can’t really judge the accuracy) picture of usage. It definitely changes values when my electric stove or dryer turn on, and it also cycles in time with my electric oven when the heating element comes on and off. So I have every reason t believe that the display is reasonably accurate.

One problem it does have is frequent dropping of the radio signal. The receiver needs to be re-sync’d frequently.

Breakdown and Replacement

Rating: ★★☆☆☆ 

However, one problem became apparent soon after installation: the sending unit simply stopped working one day. We had a very wet summer this year and when the sensor stopped sending one day the first thing I thought of was that it had leaked water. Sure enough, when I opened the battery compartment, which also houses the main circuit board, several drops of water leaked out. I took the sensor inside and let it dry for a couple of days and it came back to life. So I reinstalled it, tightening the cover extra tight in the hope that it was a leaky silicone gasket letting the water in. It wasn’t, and the sensor failed again during the next rain storm.

I called the 800 number on the front of the instructions and had some confusion navigating the menu (it announced itself for DeWalt tools, not B & D). But eventually I got to an operator and gave her the product number. Clearly this line handles all the B & D products from power tools to coffee makers, and there was no way that an operator would have any idea about the product I was describing. But she was polite and indicated that if they authorized a repair I would hear via a return phone call in a couple of days. Well, I didn’t. But abour a week later I received an envelope that had a B & D shipping label inside, with absolutely no instructions whatsoever. So I assumed that they wanted me to send this thing for repair, which pissed me off, since I really wanted a replacement and didn’t want to wait 6 weeks for a repair to be done.

But then, another week later, a UPS truck stopped one afternoon with a box and inside was a complete new unit! And again, no instructions about what to do with the old one. So at this point, I have two units, with one working sending unit. And as soon as B & D tells me whether to actually ship the old one back, I will.

Update: 9/8/2010 – B&D never asked for the old one back. I wish they would have though, because 6 months after getting the replacement sending unit running, it too failed. This time there was no water leak, it just stopped sending data. I wrote a brief, separate update here.

Overall Impression

Overall: ★½☆☆☆ 

Basically, now that after the quality problem has been solved once, I am happy with this meter. the second transmitter broke in a few months. It was easy to install, reasonably sensitive, the receiver works at a good distance, and I have every reason to believe that it is reasonably accurate. Given the initial failure that I had, I do worry about the longevity of the sending unit while it’s exposed to the weather. And I would prefer a unit that would work while my generator is running to help me monitor the load. But as a gift for around $100, I really can’t complain. feel like I’ve been ripped off due to the poor quality.

Black and Decker tech support was very confusing, but in the end it served its purpose and got the job done. I received a replacement unit and everything works. and everything worked for a few months until the second transmitting unit failed. Now I’m changing my tune – avoid this product; it’s unreliable.


The instruction manual warns that the meter could suffer interference from certain other wireless devices. In my case that appears to me the rain gauge for my Oregon Scientific Wireless Weather Station. So even after I received the replacement unit, the display seems to go to zero whenever it rains. But unlike before when the sending unit was leaking, the display comes right back soon after the rain stops. Since the other parts of the weather station (the anemometer, thermometer, and barometer) work all the time, I assume that it is the rain gauge transmitting that interferes with the display. I’ll keep an eye on this, but I’m 99% sure that it the problem.

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  1. September 9th, 2010 at 01:28 | #1

    [New Post] Whole House Power Monitor – via #twitoaster http://robsrants.havasy.net/2009/09/whol

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