Five Percent: Conserve Energy

Climate Change Is Important: Energy Conservation is the First Step

July 28, 2008

Cent-A-Meter, Centometer, or PowerCost Monitor: Pays For Itself

Category: Conservation,Green Reviews,Household,Save Electricity,Tips – Tom Harrison – 12:00 am

Not Really the Cent-o-meterI have a product, known variously as the “centometer”, “cent-o-meter”, “cent-a-meter”, “powercost monitor” and “power cost meter”. It shows your electrical consumption in dollars and cents on a little display you can put where you like. Your electrical use is no longer “out of sight, out of mind”.

Update: 3/10/2009 — the same unit is now being sold under the Black and Decker label.

And boy does it work!

I bought one and installed it, and, having received our first electricity bill since then, can confidently say that it will pay for itself in less than a year. Maybe a lot faster than that!

Update, 2009: Oh yeah, a LOT more quickly than a year!!

Where To Buy The Cent-a-Meter

I’ll call it the Cent-o-meter, because the TV show Wa$ted used that name. The model I got is officially called the PowerCost Meter, and I purchased it at the TerraPass Store for $134. Update, 2009 — BlueLine’s PowerCost Monitor is now available for about $100 at Energy Circle’s store

I found the “real” Cent-A-Meter online for $153. I have not used the actual cent-a-meter. They should both have the same result, even if they work a little differently.

Does that seem like too much to spend?

Is the Cent-A-Meter Too Expensive?

Consider that over the course of several years, my family and I have reduced our electricity use by more than 40%. Our bill this month was around $100. Our electricity rate, like those around the country, will be going up (way up). This month, we appear to have cut yet another significant percentage off our total, I think now up to 50% reduction. In other words, our bill last month would have been $200 without our conservation measures.

So if you are starting from scratch, you could easily get the first 25% in a few days, using the Cent-o-meter as a guide. In our house, that would be $50/month. Maybe you’ll get more, or maybe you pay less for electricity (now), but it won’t take long to pay for itself.

How We Cut Our Electricity Use in Half

We learned how to save electricity usage the hard way: try a things or two, wait for the electric bill to arrive, and see how we did. This method takes discipline, patience, diligence, and perhaps a mental disorder (of which I have all, except perhaps patience :-). Yes, I could have walked outside, read the electric meter, done the math, and all, but I didn’t. I’ll bet you don’t, either.

I was aided in some cases by my Kill-A-Watt meter, but that only works for things you plug in, run on 110 volts, and can reach easily. For us, this did not include the dryer or our fridge, nor most of our lights.

It took a long time. Some things, like turning out lights you aren’t using take a lot of practice. It would have been a lot quicker if we had this little display sitting in our kitchen all along, right next to our thermometer and clock.

You Know When The Dryer Is On

The PowerCost Meter works because you know within a few days what really uses electricity in your house.

When things are mostly quiet, we still use about 5 or 6 cents per hour — a dollar a day. When we’re up and about, it’s usually around $0.12 per hour; lights are on, the refrigerator is running, the computer or TV is on, and so on.

Here’s a picture from this evening — $0.09/hour, we have used $22 of electricity since I last reset and it is surprisingly cool 64 degrees outside for a late July evening.

But when I look down and see $1.22 per hour, I know the dryer is on. Holy cow!

Why Does The Cent-o-Meter Work?

In truth, it’s not the actual money that motivates me. I waste a lot of money on a lot of other things less useful than dry clothes. I know having a clean dryer vent can significantly reduce drying time, and now I feel more motivated to keep it clean. And fewer loads seems like a better idea. And I wonder if it would be practical to dry a few things on a clothes line?

The same idea works in my car (a Toyota Prius). Being aware of my mileage at any moment has affected my driving habits only because I am immediately aware of the gas mileage impact of how I am driving. There is no doubt in my mind that I am currently getting 51.9 mpg in my Prius, well over the rated 45 mpg, because I pay a lot of attention to that meter. It’s something to do, and kind of fun.

Installation and Stuff

The model I got (BlueLine Innovations PowerCost Monitor) installed easily in about 20 minutes. It has a device designed to be strapped around the electric meter, and it actually reads the meter. It can work with most common meters, even the old spinning-dial ones. Instructions were good, and there’s a special book for each different meter kind.

The meter-reader part has a wireless transmitter that sends a signal to the display part that you put inside your house. You set the date and time, and also, using a current electrical bill, enter the amount you pay for a kilowatt-hour of electricity, which is usually right on the bill. That’s all.

The actual Cent-a-meter works slightly differently — rather than being strapped to the electric meter, you wrap a measuring device around the main electricity wire to your house. Other than how they get at the usage, both devices seem pretty much the same.


  1. How do you measure the total dollar amount used if the electric company bills the kilowatts used in different tiers? Is this something that can be programmed onto the unit?

    Comment by Patrea — November 3, 2009 @ 5:29 pm

  2. The PowerCost Monitor and similar devices like the ted 5000 understand several tiered rate structures and let you enter the data. Works great! Both at available at Energy Circle and other stores on the web.

    Comment by Tom Harrison — November 4, 2009 @ 12:47 pm

  3. […] to find ways to reduce our electrical consumption by about 40%.  All of this was before we got our first electricity monitor, the BlueLine PowerCost Monitor.  Then I got a TED 5000 about a year ago when it first became […]

    Pingback by Energy Monitoring: It’s Not a Passive Thing | Tom Harrison Jr — August 26, 2010 @ 12:51 pm

  4. Take a look at It works on all the branch circuits and you don’t need to jump up and run around. It can log it all and get to the bottom of it in a week. It also helps with power factor that can be a stubborn chronic loss.

    Comment by Chris Clement — April 9, 2011 @ 5:59 pm

  5. I have had a Cent o meter Owl for many years and do look at it but could do more but it is mostly for interest.
    On the Owl it has the option of showing gm CO2 per hour based on a conversion.
    I am working on a different project now
    Can you confirm the NZ standard conversion from kW-hr to gm CO2

    Comment by Bob Baker — September 6, 2011 @ 7:09 pm

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