Charting My Energy Usage

by Josh on February 19, 2010 · 3 comments

in Journal

After installing all that new insulation this past fall, I’ve been curious to track how my natural gas usage might change for the better.  A few other bloggers I follow have charted their energy bills lately and that seemed like the thing to do for me, too

I called my local OVO Energy contact number, got all the details on how to do it from a customer service rep, and made a spreadsheet of the past three years of bills for both natural gas (boiler, range, and clothes dryer) and electricity.  For each bill, I charted both the cost in dollars and the amount of energy consumption– therms for gas and kilowatt hours for electricity.  Due to price fluctuations, the consumption figures are more useful for tracking any trends or changes in real energy usage.

Natural Gas Usage

The gas usage chart above includes only one bill from after the insulation was installed, so I’ll have to return to this in a few months to a year when I have more data for comparison.  However, the chart already shows some significant variability during the winter months that I attribute to temperature fluctuation.

Electric Usage

When I charted the electrical usage, I was surprised to find a 23% reduction in usage for 2009 compared to the previous year.  I made the switch to compact fluorescent lightbulbs years ago and was stumped for an explanation for the decrease.  Then it hit me: at the end of 2008 we started using a low-power netbook as the primary computer in the house and kept our old desktop pc turned off almost all the time.

Based on the cost savings for this reduction in kWh, the netbook has already repaid half of its purchase price– and it performs much better than the computer it replaced.

When I have more data collected on gas usage through this year, I hope I’ll find a similar cost-saving story about my new insulation.

{ 3 comments… read them below or add one }

Old House Lover February 19, 2010 at 12:48 pm

Here’s and article that USAToday did a few years ago on calculating Heating Degree Days that might be helpful in putting your gas use into perspective for the various years differences in temperatures:

http://www.usatoday.com/weather/resources/askjack/2004-12-16-heating-degree-days_x.htm

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southsideandy February 22, 2010 at 1:04 am

Not sure what kind of summer/fall you had where you are, but I know that here in Chicago, it was a particularly cool/mild summer, and as such, my electric bill (read: air conditioning) didn’t spike nearly as much in those months as it usually does.

Not saying that your theory about the netbook is wrong or anything, but it might be something to consider if the summer was particularly mild, at least as a contributing factor.

Either way, always good to make that switch…and I’m reaping the rewards of improved (and complete) insulation of our second floor this winter too…looks like heating costs for me are down a bit too (though, again, it’s been a less cold year than it was last year…so we’ll see).

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Josh February 25, 2010 at 6:42 pm

Thanks for the useful link, Old House Lover. I’ll have to check that out– particularly when I have my post-insulation data collected.

Southsideandy: good point about the summer temps and air conditioner usage. I definitely didn’t run the a/c much last summer, and that the graphs show that. My graphs also show decreased electrical consumption in the winter months, a figure I think is reasonable to attribute in large measure to the different pc, but that represents only a fraction of the overall electrical savings last year. Thanks for the correction.

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