Results from Monitoring the Meter

In a previous post Green Scene Hits Your Code, I mentioned how a friend of mine loaned me a Kill A Watz. I realize I am a bit behind on posting the results from my non-scientific home test.

For about two weeks, I had the Kill A Watz monitoring the electrical usage of our home entertainment center. Specifically a:

• Panasonic 42″ Plasma TV
• Sony DVD Player
• Sony VCR Player
• Yamaha Subwoofer

(It’s a really simple home entertainment system. And yeah, I know, the VCR is an antique. Even worse, I don’t own a DVR…which would have driven up my numbers.)

The Kill A Watz records the number of hours it is plugged in as well as the total Kwh of electrical usage. The primary goal of my test was to see how much electricity and money I would save by physically pulling the plug on all this stuff versus having it sit in standby mode. Everything is plugged into a power strip. For about one week, we just left everything in standby mode. Then for about another week, we flipped the switch on the power strip to off when we were done watching TV.

Here are the numbers from the Kill A Watz (note: it wasn’t an exact week for each run):

Stand By Mode	167 Hours	8.03 Kw	48.08 watts/hour
Powered Off	281 Hours	8.53 Kw	30.36 watts/hour

So, by out right turning off the entire system we saved 17.72 watts of electricity per hour. If you calculate this over an average 30 day (720 hour) month with the cost of electricity from my last PG&E bill, ( ((17.72 watts x 720 hours) / 1000) * $.22708 per Kwh ) you end up with a monthly savings of $2.90! Saving me about 2.5% of my electric bill.While that’s not a lot of savings, overall. It’s a start. More importantly it started me thinking about the power consumption of our house in general. The findings would be much more substantial if I ran the same test in my home office. Turning off my 4 hard drive NAS system, all my networking gear along with the computers when not in use — even if just overnight — would result in a huge savings. I actually did this a few years back when my wife and I went on vacation for a 3 weeks; physically powering down all the gear in the home office and the home entertainment center cut our electrical bill almost in half that month.Coincidentally, I recently came across an article in the Economist talking about two devices that monitor the electrical usage for your home as whole. The Owl and Wattson are both similar devices, they have a sensor that attaches to where you power comes into the house and a remote display that shows you your usage. The Wattson has more stylish flare as well as the ability to output data to a computer for further analysis, but today is only designed to be used in the UK (both actually come from the UK). Both do essentially the same thing, let you view your power consumption in real time.

It is amazing to see how much energy different items in your house consumes. One thing I noticed with the Kill A Watz is that when the plasma TV is running, it consumes between 200 and 400 watts of power depending on if the scene is dark or bright. A curious discovery. While these types of gadgets don’t do much on their own to save electricity, the awareness they help raise is a great start.