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!