Five Percent: Conserve Energy

Climate Change Is Important: Energy Conservation is the First Step

October 31, 2009

Google PowerMeter: New (Useful) Features, New Device

Category: Companies,Conservation,Save Electricity,Save Fuel,Technology – Tom Harrison – 3:09 pm

I expected nothing less of Google PowerMeter — week by week, it continues to improve. Now the graph displays my usage compared to expected use, and includes a visual and numeric accounting of my baseline, “Always On” usage compared to total usage. Here’s what my graph for today looks like:


Three Great Things

The expected usage gives you a nice target, and the comparison to others provides a helpful benchmark.

But the new “Always On” measure provides two very helpful bits of information.

First, the darker bar helps isolate the spikes above. For example, the most obvious repeating spike above is the refrigerator — it cycles on about once per hour and runs for perhaps 25 minutes each time, running at a bit over 200W — it’s easy to see that pattern.

It’s also easy to get a rough estimate of the fridge’s individual contribution to my whole household use doing some simple math For example, it’s running about half of the time, using about 200W when running. This is the same as 100W all the time. If I know my electricity rate (I do, it’s 19.2 cents per kWh) I can do some math: 100W = 0.100 kW * 365 days * 24 hours * $0.192: this fridge costs about $45/year $170 in electrical costs (thanks to Ash for pointing out my math error!).

Second, the baseline is as clear as day: a bit less than 300W, which represents 7.1kWh/11kWh, or about 65% of my total electrical consumption. And that fridge, adds 100W to my overall baseline usage of around 300W.

Hmm, that means my fridge uses about 876 kWh per year. So let’s look at the EnergyStar site for comparable units (our current one is 22 cu ft), and we can see that the most efficient refrigerators sold today use 403 kWh per year — less than 1/2 of my 11 year old model. Wow! On the other hand, a fridge costs about $1,000, so I guess we’ll hold off until it stops working consider whether a 6-year payback makes sense for us.

Both of these data are things I can actually do something with. I would like to reduce my baseline/Always On number. Maybe I’ll follow my own advice and add a light timer to the TiVo, or even Internet connection and turn them off between 1 and 6 in the morning.

Similarly, the 6pm to midnight lump is just when we’re all home, at night with lights, dishwasher, TV and the like turned on. This just puts our usage in perspective.

The Third Good Thing

The Energy Detective (TED 5000) was the first device partner; a new UK company sells a similar and simpler looking device that also works with Google PowerMeter, called “Alert Me”. What is especially interesting is that they have a deal with a natural gas company — the device just knows how to read meters. While providing less detail than the TED, there is more to our energy picture than electricity. I am anxiously awaiting this product for sale in the US.

Progress is happening!


  1. […] This post was mentioned on Twitter by Tom Harrison and Solar Panels, John Power. John Power said: Google PowerMeter: New (Useful) Features, New Device | Five … […]

    Pingback by Tweets that mention Google PowerMeter: New (Useful) Features, New Device | Five Percent: Conserve a Little Energy -- — November 1, 2009 @ 5:06 am

  2. Love the website. Lots of great info. I’m considering implementing the TED also. Anyway, I’m looking at the refridge power use calc and I’m not getting the same annual cost.

    I’m getting $168. I’m I missing something?

    Comment by Ash — December 3, 2009 @ 10:43 am

  3. Ash —

    The annual cost depends on your electricity rate and the amount of power your fridge uses. If the fridge is 15 years old, it probably uses 2x to 3x as much as a comparable 8 year old model, which uses at least 2x as much as a current model.

    EnergyStar is hard at work – all of these (incredible) reductions are a result of a government run, voluntary program. Pretty cool, eh?

    Comment by Tom Harrison — December 3, 2009 @ 4:49 pm

  4. Thanks for the EnergyStar “sell”. I’m a firm believer in doing what you can to control energy cost and helping the environment, but he main reason for post was to question how you arrived at $45/year energy cost of the refridge.

    When I use your numbers I get $168.192

    0.100 kW * 365 days * 24 hours * $0.192= 168.192

    I’m I doing something wrong? The equation looks correct.

    Comment by Ash — December 7, 2009 @ 8:45 am

  5. Ah, yes, well, er, that would be different. Thanks for correcting the error. I have updated the post.

    I have no idea how I came up with that $45/year number — I must have checked it twice incorrectly, because when our electrical rate was a little higher, I recall thinking a rule of thumb was that each 100 W, always on, cost about $200/year.

    If I recall correctly, the average electrical rate in the country is about $0.10/kWh, about half what we pay here in New England, so a general rule of thumb for the country might be close to $100 for every 100W.

    Sorry for giving you a dumb answer to a smart question last time!

    Thanks again —


    Comment by Tom Harrison — December 7, 2009 @ 8:01 pm

  6. How great it is to see home energy monitoring come of age, and be able to play a real role in increasing the awareness of how and where energy is being used.

    Monitor in hand, a wattsup smart circuit 20 in our case, and the energy audit complete we were ready to take action. We made the “no investment” changes first, turning lights off, turning appliances off, power settings for the laptop, fridge settings, acceptable compromise in apartment temperature, and did not fall for vampire power scams but made sure we did not have any offenders.

    Lighting was next, first the obvious CFL replacements, and more recently a 100% replacement thanks to an on-line supplier of reasonable candelabra, dimmer, and A19 bulbs. We have a graph of the before and after energy profiles and a real incandescent vs. CFL analysis – 2 days of the old – 2 days of the new. Our outcome, a 75% lighting saving on electricity.

    But then came the issues, what about the increased energy cost of CFL manufacture, what about the mercury, what about the 55% CFL power factor, and finally what about our apartments overall power factor. I happen to know quite a lot about power factor, so it did not take me long to establish that our fridge circuit was at 91%, our appliance circuit 91%, our furnace fan in regular operation 80%, and our lighting circuit had dropped from 100% with or the incandescent bulbs to 75% with the CFL’s

    I was pleased it was 75%, and not the 55% as one web site claimed, quality bulbs do have quality electronics.

    Readers please take note, ALL of the issues I have raised above are NOT of significant concerns. But all are them are being trumped up to promote some untoward purpose in the disinformation.

    The mercury in a CFL is less than the amount which covers a pencil tip, the recycling facilities are all in place, with a 10x greater life and a 75% energy reduction CFL light bulbs are a sound energy saving strategy. The real issues are the time they take in certain use cases, like a bathroom, to reach full intensity. It may not always be OK.

    The bigger issue is power factor. Besides being used by the incandescent advocates to scare us away from CFL’s, for as I demonstrated above they do have a lower power factor, it is being used to market power factor correction technologies.

    From scam gadgets you plug in, to sophisticated home automation systems which do correct power factor, but have no purpose in domestic consumer use.

    In summary, when the power factor is less than 100% it means that there is a phase shift between voltage and current. Consumer tariffs are based on Real Power, only the electricity actually consumed by a device. The consumer electrical tariffs include provision for the power factor losses which this “out of phase” might cause the electricity supplier.

    It is true that electricity suppliers need to manage their distribution networks, and that power factor IS one of the factors that impacts their distribution losses. It is also true that large industrial users are charged a penalty for a net power factor of less than 85%. But distribution losses will not be solved by consumers. They are aggregate issues that can only be solved by the utility companies (the smart grid) in partnership with industry and device manufacturers.

    Power factor and power factor correction are indeed subjects that we should be aware of, but it is fraud when marketed to home owners as a way to save money on their electricity bill.

    Here are two articles I encourage all consumers to be familiar with, and please let others know so that none of us are duped out of our hard earned cash.

    A list of products wrongly claiming to save electricity through power factor correction, plus a couple of other scams – Energy Saving Scams

    A detailed explanation of power factor correction and why it does NOT impact a consumers electricity bill, or reduce the effectiveness of CFL energy savings – Power factor Correction – Scam Review – a note of thanks to David Stonier-Gibson of SPLat Controls, who gave us permission to publish his article on power factor !

    Comment by Alex — December 31, 2009 @ 6:30 pm

  7. Another featured device of Google PowerMeter is the Envi. It is interesting to me that no one ever mentions the Envi. Maybe I am just showing partiality to it because I know about it, but I really do feel like it is the underdog that no one ever mentions.

    Comment by Energy monitor — August 23, 2010 @ 9:18 am

  8. Dear “Energy monitor”

    Please don’t spam my site. Your link happens to be to a company that just happens to sell this product. I have changed that.

    Nobody mentions Envi because it has only been for sale in the US for a few months now, and it’s not that great a product. I put a small review of it on the other spam comment you posted, in short, it’s a pretty weak product compared to other options out there.

    Comment by Tom Harrison — August 23, 2010 @ 10:30 am

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