Energy usage notes

My electricity bill is just terrible now, $500 / month. Since we moved in we’re using 800-1200 kWh / month, or about 1400W average usage all day every day. We’re both home all day and use computers, so I expect our power usage to be high, but that’s absurd. Where’s it going?

Now that we have a Smart Meter, PG&E has an awesome “My Energy” site where you can see hourly energy usage for your house, per day. Here’s a typical day, Tuesday January 24, 2012. We tend to be awake from 7am to 10pm. (I also have a private graph for the whole month.)

Looking at this, it’s clear turning the lights on in the morning and at night has a big impact. Our house has terrible lighting design, a lot of light wasted in ceiling cans. Also still all incandescent bulbs, although on fancy dimmers that should lower power usage.

What really surprises me is the constant usage of 700W all the time, even when we’re asleep. We turn the lights out at night! And sometimes it’s worse, up to 1000W. Fixing that nighttime usage seems like a good place to start.

Here’s a quick audit of things I know take constant power.

  • 150W Wine cooler (450W when active)
  • 50W Refrigerator (average)
  • 120W My computer (when in use)
  • 200W Ken’s computer (constant)
  • 50W Linux server (constant)
  • 80W A/V rack (when idle)

That’s 650W right there, all the time. We can easily turn off my computer and Ken’s computer, that’d cut about 300W out of the wasteage. My computer already goes down to 30W when idle but I can make that 1W. Ken’s computer is awful; it never goes to low power mode and the monitors constantly wake up in the middle of the night. I don’t know why, it’s a Windows 7 box.

I just unplugged the wine cooler. It’s really not necessary in winter. It’s insane that it runs one third of the time even when it’s cool outside; the manual says something about maintaining humidity. Paying $40 / month to keep my wine at 54F instead of 65F seems stupid. It may be more power than that, btw, the Kill-a-Watt registers 450W but 750VA. The website says it draws 6 amps when running, which is more like 660 kWh/hour, yes?

It’d be nice to shut down the A/V rack. But the Tivo is actively doing something useful, and that’s half the power. The other half is keeping a bunch of Sonos units running at 5W each. Probably not worth the bother to buy a timer or something.

Other ideas

It’d be awfully nice to get the usage data in real time off my meter and not have to wait 2 days for it to show up on the website. The buzzword for this is “Home Area Network” and PG&E, of course, is slow to deploy. No doubt in part because they have to worry about the insane people with imaginary diseases. Anyway, here’s some info on a HAN trial.

It’d be nice to install a solar panel on my roof. SF Solar Map estimates I have 1300 sq ft of space for panels which is good for 5kW. At 4.5 hours of sunlight / day that’s 6324 kWH / year, or about half my electricity usage for the year. A 5kW system costs $32,000, but after incentives the cost to me is $21,000. It’d save me about $2600 / year so I’d break even in roughly 8 years. A 2kW system would cost $7400 and break even in about 7 years. (Cost estimate assume $6.50 / W-dc, which may be optimistic.)