Just Bought an Energy Meter!

Ever wonder just how much electricity you use when you sit in front of the tube for three hours? When you toast some bread? When you boil water for a cup of coffee?

These are the things that keep me awake at night, until I start worrying about how many kilojoules I’ve wasted keeping the lights on.

So to put my mind at rest and reduce our light bill, I went out and bought a simple energy meter. I’m hoping it will answer some of these questions, and shed some light on our energy usage-habits.

Yup, today I went down to Conrad and bought an Energie-kostenmessgerät. That’s a long German word that means “energy meter”. It cost about €10.00, which these days amounts to about US$ 15.00. Not a budget-breaker by any means, but if you have a friend who’s already got one, you might as well borrow it anyway!

This is what mine looks like:

Now don’t be frightened by those odd-looking holes in the meter. That’s just a German- or Western-Europoean style electrical socket!

Using the meter is pretty simple: you just install it between your electrical gadget and the wall socket:

I first tested the meter by performing the energy-intensive task of  boiling water. I dumped 500 ml (about a pint) of water into our Braun water cooker and brought it to a boil.

The meter has several screens that allow you to see various statistics regarding your usage. I imagine that most of the low-cost meters out there have similar screens. After barely a glance at the instructions, I was able to figure out the screen that told me how much energy I used, and how long I had been measuring:

That’s right! It took about 82 seconds to bring 500 ml of water to a boil, and it used a whopping 0.034 kilowatt-hours of energy!

The meter also has a feature where you can enter two different rates, and it will show you how much money you’ve burned up. Since I’m from Seattle, but live in Munich (Germany) I thought I’d enter in typical kilowatt-hour rates from those two cities:

There are probably a bunch of taxes on top of those prices as well, but I just wanted to get a rough idea of what the costs might be.

This web site is actually more about understanding the actual amount of energy used to perform tasks. Ie: how many Spotted Owls need to be sacrificed, how many acres of rain-forest cleared, how many barrels of oil need to be burned, or how many grams of CO2 produced in order to get the energy for a particular task. But I suppose that monetary cost is one pain point that helps us get a feel for

Another interesting set of screens shows the high and low wattage during the measuring. We can see that the water cooker pumps some serious juice, and it varies by over 300 Watts during the cooking!

This info might be useful when measuring devices that “go to sleep”, like LCD and Plasma television sets and monitors.

Anyway, knowing the amount of energy used (kilowatt-hours) and the price-per-kWh allows the device to calculate your costs:

So to boil that pint of water in Seattle would cost about two-tenths of a cent, while in Munich it costs over three times as much! (note: €1.00 is about $1.50)

The cost feature is nice, but I think it is just as easy to take the total kWh reading and use that in an Excel or Google Documents spreadsheet. As I mentioned earlier, it’s not just the dollars we’re interested in, but what exactly X kilowatt-hours really means.

I’m looking forward to seeing how much energy our devices use, especially when they are idle or “asleep”. So look forward to some Green World Pictures in the coming weeks that illustrate the energy we use and the energy we waste in terms of things that are easy to understand!