Last Saturday's stats post caught the attention of Steve Balogh, a blogger for Groovy Green. He questioned how my wife and I could use 8,522 kWh of electricity in 3 months, and pointed out that was an average of 2,840 kWh per month, or 94 kWh per day, while he only used about 15 kWh per day in his home.

Over the course of the past week, Steve and I have exchanged emails and information about our respective uses of energy–not just electricity, but any home heating source. Turns out that Steve heats his home with natural gas, which would explain why his electricity use averages just 15 kWh per month. Steve converted therms to kWh and did the math on his total energy use and came up with an average energy use of 5,474 kWh per month for the first three months of the year!

Now, the point of all this isn't to compare Steve's and my use energy head-to-head. According to Steve's Groovy Green bio, he and his wife live in a 1905's home in Syracuse, New York that they are trying to upgrade to 2010 specs. Alisan and I live in a 10-year-old townhome that is reasonably energy efficient.

The point of this post is twofold:

1. to further explore what's going on behind the scenes of my energy use, and 
2. to encourage folks to follow the 10 steps to 10% energy reduction by 2010 that Teton County Commissioner Ben Ellis and I presented last Saturday at Eco-Fair

So, here's what I've learned about heating degree days and how they affect our energy bills.

According to Wikipedia:

Heating degree day (HDD) and cooling degree day (CDD) are quantitative indices demonstrated to reflect demand for energy to heat or cool houses and businesses. These indices are derived from daily temperature observations.

Heating degree days are calculated over a period of time (typically a year) by adding up the differences between each day's mean daily temperature and the "balance point" temperature of 18°C (or 65°F), above which the building is assumed not to need any heating (the actual indoor temperature will be higher due to insulation retaining heat from the occupants). Thus three successive winter days with average temperatures of 4°C, −2°C and −4°C totals to 56 HDD. Conversely, three summer days of 26°C, 28°C, and 30°C totals to 30 CDD. For differences between day and night temperatures, the average is taken; so a day maximum of 10°C with a night minimum of 2°C averages to 6°C, or 12 HDD.

According to my friend at Lower Valley Energy, Brian Tanabe:

• Wyoming ranks among the top-five states, on average, for highest number of heating degree days per year
• Jackson averages 25% more heating degree days than the state average
• Jackson averages 98% more heating degree days than the U.S. average
• January 2007 was the coldest in Jackson since 1985
• Jackson's January 2007 data (1814 heating degree days) is higher than the annual average for states like Arizona, Georgia and Louisiana!

That certainly helps explain why our electricity use was up significantly (19%) this winter compared to last–even while we were trying to conserve. What it doesn't explain is why our natural gas use was down significantly (60%) over the  same  comparative period of time. (I would guess that quitting the gym, which led to heating my garage with an electric heater frequently, lead to more electrical use, while the rising heat from the garage lead to less need for heating the living room above with natural gas?)

Bottom line: home energy use–and the climate that affects it–has to be examined thoroughly before you can begin to develop an effective conservation strategy. I'm just beginning to delve into ideas that should help conserve more energy next year, no matter how the number of heating degree days change.

Steve was kind enough to thank me for helping him put his home energy use in perspective. I'll return the sentiment and thank him for making me dig a little deeper to learn about the dynamics that affect all of our energy bills!

Carbon Neutral Journal's stats are brought to you by Blue Spruce Cleaners.

Popularity: 13%