One of the major challenges with the Kill-A-Watt is it requires that the device to be measured must be unplugged and then plugged into the Kill-A-Watt’s front receptacle to measure energy consumption.   This precludes measuring consumption of direct-wired devices such as lighting and dishwashers, along with 220V appliances such as electric dryers.

Measuring the consumption of the entire household can also provide interesting and useful data – for example, what is the ‘always-on’ consumption?

The easiest way to measure the consumption for the household is to do it at the meter.  Unfortunately, most meters do not provide that data to the consumer directly; some newer meters being deployed as part of utility Smart Grid initiatives support ZigBee, but those are not widely deployed.

Several years ago a company called Blue Line Innovations created and patented (US 7174260) a device to accomplish this.  Consisting of two parts – a transmitter which attaches to the household meter and a remote display – it can monitor the near real-time usage through the meter.

It does this via one of two mechanisms within the meter-mounted portion of the device: for old mechanical dial meters there is an infrared transmitter and receiver which monitors the rotation of the dial. Newer meters have an IR transmitter on the front or top of the meter itself which periodically pulse to indicate usage;  the infrared receiver of the monitor can be located to pick up that pulse.  In either case, the unit is mounted to the meter via a standard hose clamp and sends the consumption rate to the remote display.  Approximately every 30 seconds the display updates with the current energy usage along with calculated cost information based on the rate the user programs into the display.  Month to-date and estimated monthly consumption is also provided.

Black & Decker resells this device under their label as the EM100B Power Monitor.

On the positive side, this device is relatively easy to install (with some caveats), provides a near real-time view of total energy consumption, and has decent range.  A very useful feature is a ‘tare’ display, which essentially zeroes out the current consumption so that the user can turn on an appliance – say, a microwave oven – and see the delta energy use and cost that the appliance requires.  This is also useful for lighting – comparing incandescent bulbs to fluorescent in the same fixture, for example.

There are some challenges with the device, however – the first unit I had died within two weeks.  The second one failed within a year, although B&D refunded the cost of the unit.  Lining up the infrared receiver to pick up the pulses is relatively straightforward, but I had difficulty receiving data if the sun was shining directly on the meter.  Batteries in the transmitter must be periodically replaced, and given exposure to outdoor temperature extremes lithium AA batteries are recommended.

Additionally, there is no supplied mechanism for storing and collecting the data, although recently Microsoft and Blue Line have announced a WiFi option ($150!) to permit data to be collected by Microsoft’s ‘Hohm’ .  This lack does make tracking consumption changes over time difficult at best.

The EM100B is a good option for someone who wants a relatively simple whole-house monitor – but there are better solutions if more detailed information is desired, including the subject of the next post, the Energy, Inc. TED 5000.

The simplest method to identifying the energy use in your home is to measure it appliance-by-appliance.  While one could go around with a multimeter and perform some calculations there’s an easier method: the P3 International Kill A Watt.  This is a small module which plugs into an outlet and has a front-facing receptacle into which you plug the appliance or devices you want to measure.

The display will show real-time consumption in watts as well as real-time current.  Consumption over time is shown in kilowatt-hours (kWh), the unit by which electric utilities measure for billing.  Kilowatt-hours are calculated by multiplying the power in watts by time.  For example, a 100-watt lightbulb left on for an hour would consume .1kWh of electricity.

Additionally the unit will show other characteristics of AC power such as voltage, frequency and power factor.

The Kill A Watt is straightforward in use, with one downside: you have to unplug what you want to measure.  Not a big deal for a fridge but it’s annoying when you want to measure a computer system.

That said, I was able to determine with the Kill A Watt that my old home server was consuming around 180 W 24×7.  That worked out to 1577 kWh/year, and at my electric rate of $0.1605/kWh the server was costing me about $253 per year to operate.  Whoa.

I replaced the tower server with a Mac mini server which consumes about 15 W.  That results in an annual charge of about $21.

Big difference!

I also was able to determine that my home entertainment system – LCD TV, amplifier, Xbox 360, Blu-ray player – when turned off still consume about $70 of electricity per year.  This is because those devices have a ‘standby’ mode which allegedly reduces the power-on time but essentially just a waste of money.  Typically these loads are referred to as ‘vampire’ loads.  I didn’t include the DVR in the calculation since that is legitimately left active – though there is certainly opportunity for decreasing the energy use of those devices as well.

Other computers in the home also added up to another approximately $30 per month by not being correctly configured to go to sleep when idle, or in the case of an XP machine, ignoring that configuration and remaining on in spite of my best efforts.

The challenge with the Kill A Watt is that you can only measure what you plug in; it is not useful for monitoring things like central air conditioning, lighting, etc.  For that, there are some other options which will be covered later.

The 30 second summary:

• Left my employer, Ambient Corporation, after almost six years; it was a nice run – a personal record, in fact – but it was time for a change;
• Hooked up with some people to launch a smart grid startup focusing on substation automation, for which we have been pursuing venture capital funding;
• Continued to evaluate other employment opportunities;
• Had a lot of fun with my family; continued to be involved in Little League and other activities.

More to follow.

After an all-too-brief period of relaxing and catching my breath, it’s time to figure out what’s next.

Some postings didn’t survive the server changeover. More accurately, the server expired, but perhaps someday I’ll get around to pulling data from backups.

Random stuff on twitter – avoiding “I had chili for lunch” messages – but should dust this thing off..

See threat #1 at the 5:43 mark.

Nice shot on the Zune, too.

Apple Remote is kinda cool, NetNewsWire works well, AIM is, well, AIM.

Next to try is OmniFocus..

Oh, yeah. And the 3G comes out tomorrow. Sigh.

“Dice-size crumbs of bright material have vanished from inside a trench where they were photographed by NASA’s Phoenix Mars Lander four days ago, convincing scientists that the material was frozen water that vaporized after digging exposed it.”

Ice on Mars.

Sweet. (apologies for the 1990 flashback)