Tuesday, June 30, 2009

Home Energy Consumption Update

Time now for another Home Energy Consumption Update.

June of last year, we used 457 kWh of electricity. This year we used 605. The difference is that last year at this time as unseasonably cool and rainy, allowing us to open the windows and not need the air conditioning. This year, it has been in the high eighties to mid nineties almost every day for weeks forcing us to use the AC all day and many nights. Though we also have installed an additional seven or more inches of insulation in the attic, the temperatures are just too high to be easily beaten.

So for the last year, our numbers are up. The bad kind of up. When compared to the average US home, we are now 76% rather than 73% and per square meter consumption is up to almost 71 kWh.

Water use is also up due to the fact that we have a larger garden this year, and the drip system is set up to water it every morning at 4. When it rains, we can turn it off, but it has not been raining often. However, because we use the sawdust toilet, our water consumption is still far below the average American.

Some good news! I finally bought a Kill-A-Watt. I got the EZ model even though it costs almost twice as much at $35. I got that one because it offers more features. It measures volts, watts, amps, power factor, kilowatt hours, time, and has a backup in case it gets unplugged or the power goes out. I bought it not only to check power consumption for appliances and gadgets, but also for use as a monitor for my generator project. I am building a generator using a rototiller engine, a car alternator, an inverter and a deep cycle battery.

Here's some info.
Indoor AC blower off 15 watts, on 450.
Entertainment center, everything off, 15 watts, everything on, more than 200. The Xbox uses 60 watts when on. TV=50.
Washing machine, off, 0 watts, water filling 12, washing 450, spinning 600 down to 350.
Laptop, on but not charging, about 15 watts. The power supply is rated at 75, I assume that's running and charging concurrently.
Using the kWh feature, I found it takes approximately .25 kWh to wash a normal load of laundry.
The refridgerator uses about 5 watts when not cooling, 18 with the door open and light on, and 230 when running then levels off at about 200. It is rated for just over 1000 kWh per year.
The box fan we use in the window uses 67, 91, 118 on its three different settings.

Things I'd like to find out are my computer (desktop,) the gas furnace, air compressor, phone chargers, other chargers, the shop, and the modem/router.

The unit itself does say that it uses about 1 watt, so remember that.
Also, I did a bit of math for you, and you can calculate the yearly cost of a parasitic load by taking the number of watts it uses and multiplying that by 8.76 to get the number of kWh used in a year. For instance, the AC uses 15 watts*8.76 = 131.4 kWh. Muliply that by your electricity rate, for me about $.11 and it tells me that it costs me about $14.46 per year just to keep the thing plugged in. Sucks right?

Great helpful tool for conserving energy, get one.

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