A TED report on Earth Day

Last weekend while Benjamin was working, I decided to determine two things:

  • our electricity usage baseline
  • which devices contributed to that baseline and by how much

Like any performance analysis you need to start with a baseline: where are we now. I wanted to see how much electricity in kW our house was using with everything turned off. Of course “everything” isn’t, well, everything — it’s everything you decide to have explicit control over. For instance – while I’m all about reducing our electricity usage, I’m not going to go around unplugging our microwave, oven, washing machine, and alarm clocks at every turn. All of these devices use some amount of electricity to display clocks or respond to the ‘on’ button.

So with every reasonable thing unplugged or turned off on a beautiful Saturday afternoon, I loaded up my good friend TED and observed that we use ~0.168 kW. I then went through the house with my Kill-a-Watt to find out which of those always-plugged-in devices were using power and how much. Here’s what I found:

  • UPS = 34 watts
  • 3 alarm clocks @ 5 watts = 15 watts
  • 1 microwave = 7 watts
  • 1 wireless router = 5 watts

That only accounts for 61 watts, or 36% of our baseline. There are several other devices which I know use some power but I didn’t get to measure yet due to it being a pain to get to them:

  • cable modem (always on)
  • 5-port hub (always on)
  • oven (has digital clock)
  • washing machine (non-physical switch)
  • dryer (non-physical switch)
  • hot water heater (gas unit but plugs into wall too)
  • garage door opener
  • radon mitigation attic fan (always on)

Sadly, the UPS does not have a physical switch so even after turning it off the only way to stop it drawing power is to unplug it and it’s simply not worth the effort to me at this point.

Our current electric rate is $0.11883 per kW, so the smallest our electric bill could possibly be (excluding service fees and taxes) is $14.37 (0.168 kWh * 24 hours per day = 4.032 kW per day * 0.11883 = $0.47 per day * 30 days per month = $14.37 per month). Granted, we have to actually live in the house, so it will never be that low, but that give me our lower bound.

During the past few weeks I discovered some other interesting datapoints:

  • My computer, which is on at least 9 hours every day, only uses around 30 watts.
  • Benjamin’s hair dryer uses ~1 kW – which explains why the time he gets ready for work is often our peak kW usage during the day unless we turn on the oven…
  • The oven uses ~3 kW.
  • The clothes dryer uses ~3 kW off and on throughout its cycle and drops down to ~1 kW at other times. That’s unsurprising once you think about it – you’re not baking your clothes, you’re introducing hot air, tossing the clothes around a bit, and then more hot air.
  • The iPhone charger, as well as most other wall-worts, don’t actually use electricity unless they are being used. I was under the incorrect impression that these AC/DC converters would use some small amount of electricity while plugged in but not being used.

It’ll be very interesting to see how the electricity usage changes this summer when our AC kicks in.

My new friend TED

From my IBM bonus this year we purchased Benjamin’s college ring and my new friend TED 5000. TED is short for The Energy Detective – a device that installs in the electrical box in your house to measure the electricity usage. After a bit of wrangling yesterday1 I was able to get it installed and working and can geekily report that as I type this, we’re using 0.258 kWh. A point in time measurement is interesting and can be somewhat useful (it was educational for instance when we turned on the oven last night and the usage jumped an entire kWh) but trending data is much valuable and TED does that too.

The TED Footprints interface is accessed directly from a browser on the local LAN which renders it less useful for showing others. Thankfully the TED 5000 works with Google PowerMeter so I can know how much electricity we’re using when I’m not even there. That takes geeking to a whole new level.2

Armed with TED and another new geeky tool called the Kill-A-Watt I’m getting a much better picture of where we’re using and wasting electricity. Benjamin just shakes his head and loves me anyway.

More data and revelations to come I’m sure.

1 There are two pieces to the TED 5000: the MTU which sits in your electrical panel and the Gateway which plugs an electrical outlet and connects to your router. The MTU gathers the data and sends it to the Gateway using Power Line Communication (PLC). To do this the MTU connects to both A and B 120V sides of the power line so no matter which side the Gateway is plugged into, it can receive the PLC signal [aside: I’m probably using not-exactly-correct electrical terms here — there’s a reason I went Computer Science instead of Computer Engineering]. Unfortunately some devices, like UPSs, can obliterate the PLC signal if it’s on the same circuit. This was initially my problem as the most convenient outlet to plug the Gateway into was on the same circuit as the UPS for my computer. If I unplugged the UPS it worked great. If the UPS was plugged into wall, it stopped working. Drat. Thankfully the cables into our breakers are well labeled and I was able to locate an outlet in the basement that was on the A side not on the B side with my computer equipment. I plugged the Gateway into the A-side outlet, connected the MTU only to the breaker servicing that outlet and off we went.

2 Google’s too mainstream to be truly geeky. This takes us to a whole new level: the entire set of trending data is available through an API. Some folks have already developed some cool 3rd party apps, including an iPhone app. It should be pretty simple to develop a gnome-based applet that reports my real-time kWh usage via these APIs. More things to play with in my non-existent spare time!