$639! That’s up $100 from last month and more than double any bill from last winter.

I know it’s been a cold winter, but… what the …?!

We’ve had problems with the furnace, a geothermal unit that’s supposed to be energy efficient, but… what the …?!

We had even sealed off the upper floor where our bedroom is and have been living downstairs for the entire month to see if we could trim our bill!

Cecie, my better half, called the electric company to find out what, if anything, we could do. I pulled out our furnace repair bills from the filing cabinet, and we compared notes. We told the lady at the electric company the dates on which the heating guy was at our house.

Turns out that on 1/13/2010, the day after he replaced a circuit board in the furnace and recharged the system, our electricity usage dropped by about half the previous day’s usage and stayed that way for some time.

Two weeks later, on 1/26/2010, the furnace was on the blink again. The heating guy came out to fix it that same day. The lady at the electric company said from that day forward, our usage was back up.

I asked Cecie to ask the lady from the electric company if she could send us a daily usage report for the past month. The lady said sure, but you could get the data more quickly by going to MyUsage.com.

I immediately headed to MyUsage.com, logged on, created an account, and pulled up a list of our daily electricity usage. Unbelievably cool! Why hadn’t I known about this?! You can even have your daily electricity usage emailed to you and/or have a warning emailed to you when your usage exceeds a particular level! (Not all electric companies are plugged into MyUsage.com.)

Then, I headed to the Weather Underground and pulled up a temperature history for my Zip code, so I could see whether the correlation in electricity usage was due more to temperature changes or our furnace woes.

From the data, I could clearly see that the correlation was directly related to our furnace woes. Note the bold rows where dramatic changes in our electricity usage occurred. These dates correspond to visits from the furnace repair guy.

To trim our electric bill, I considered taking our second refrigerator out of service. I was curious as to how much that would save us per month, so I plugged my handy Kill A Watt EZ Electricity Usage Monitor and plugged the refrigerator into the monitor to find out.

(The refrigerator is a 21 cubic foot, freezer on top, Frigidaire, model #: FRT21NNC.)

The answer? By unplugging our second refrigerator, we would stand to save a disappointing $66 a year. We would only be saving $5.50 per month by unplugging it. Next, I’ll test our side-by-side model, which we open and close much more frequently.

My last electric bill was a whopping $566 – just what I needed to motivate me into thinking about energy conservation. (My bills generally run around $250 in the winter. I suspect that most of the increase had to do with the fact that our geothermal furnace wasn’t working properly during the deep freeze of December 2009.)

At any rate, we sealed off the upper floor, where we suspect much of our heat was going; swapped out some incandescent light bulbs for compact fluorescent bulbs; and tried monitoring our electricity usage more carefully.

I suspected that leaving my computer on all the time was probably gobbling up a lot of electricity, so I purchased a Kill A Watt EZ Electricity Usage Monitor to find out for myself. I plugged the Kill A Watt unit into the nearest outlet, entered my cost per kilowatt ($.109 or almost 11 cents), plugged all my computer devices into the unit, and then checked back 24 hours later.

I used the computer for about 10 hours, and it remained on for the other 14 hours. Here’s everything I had plugged in:

• Dell Dimension 8100 desktop PC with two hard drives, CD-ROM, and speakers
• Sony 15-inch flat-screen monitor
• Netgear wireless router
• Wildblue satellite modem
• HP Officejet Pro L7580 printer
• 4-port powered USB hub with thumb drive
• Electric pencil sharpener

The result? It costs me 40 cents per day to keep my computer running constantly. That’s $2.80 per week, $12.00 per month, and $146 per year. My computer wasn’t quite the energy hog I had suspected. I could save $70 a year by turning it off for half the day, but I’m not sure that would be worth the savings.

I’ll be checking some other devices in the coming days – the second refrigerator, the washing machine, my TV/DVR/DVD/VHS, and so on. Stay tuned.