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DayCreek Journal

March 7, 2005

2004-2005 Heating Season Statistics

Solar Output: June 04 through February 05

From June of 2004 through February 2005, the 4.2kW solar PV array has produced 3,213 kWh. This is below the predicted value of the PV Watts program, but weather does vary year-to-year. January was way below the expected output and has put us in the hole from a prediction standpoint —that's the bad news. The good news is that as I write, we have over 800kW hours of surplus—meaning that more electricity has been produced than consumed since June of 2004. Due to a warm and somewhat sunny February, the electric boiler never came on once. The house was heated passively and actively by the sun and by our wood stove on cloudy days. There were periods of 3 to 4 days of good solar heating. This did a good job keeping the sand bed warm enough to put a meaningful dent in our heating requirements for the month.

Month Forecasted (kW hrs) * Actual (kW hrs) Difference (kW hrs)
June 462 452 -10
July 506 491 -15
August 454 442 -12
September 384 496 +112
October 395 279 -116
November 249 266 +17
December 220 224 +4
January 383 234 -149
February 380 329 -51
Total 3,433 3,213 -220
* Based on PVWatts forecasted energy production.

For those of you new to our journal, our house is not totally lived in yet. I do spend more than half my time here at the house, but there are times when I am in Illinois. Once Jo moves up here, I do expect that we will use more day-to-day electricity, but actually less electric boiler heat. How so? Our electric boiler is only used to keep the house from getting too cold when I am not here to stoke the stove. Once both of us are living here full-time, the need for the electric boiler backup heat will be minimal.

Once we are fully moved into the house, our annual consumption should be somewhere in the neighborhood of 4,000 and 5,000 kWh per year. Lighting is provided by compact fluorescent bulbs, our refrigerator uses a little less than 1kWh per day and most of our water needs are fulfilled by a cistern that only requires a jet pump to pump water into the house. Yes, we also have a well, but it only rarely gets used. Our solar heating system uses no utility electricity (pumps are solar powered) and energy-star ceiling fans are used for air movement.

Out of all appliances, the refrigerator is the most important appliance to consider— they run 365 days out of the year and use a compressor. The average new refrigerator uses around 800 kWh's per year, and older refrigerators can use up to 2,000 kWh's per year. That's anywhere from 10% to 20% of a home's annual energy consumption. (By comparison, our Kenmore model #73982 only uses about 360 kWh's per year.)

I realize the number seems frightfully low to most. I did some checking with our local utility and found that the average, rural residential customer for our area in 2004 used 1,322 kWh per month. That comes out to 15,864 kWh per year. This number does include small family-owned farms, so it is slightly skewed. Looking at the national average, it is somewhere around 10,000 kWh per year.

Using the national average how can one exist comfortably using only a half of the average electricity? Well...having a very energy efficient home goes a long way towards cutting electric bills for a start. Plus, add in energy efficient appliances and a solar heating system and it really does make a substantial difference.

So how much money was spent on this winter's fuel bill?

  • Less than $40 in off-peak-rate electric heat (780 kWh)
  • Just about 1 full cord of wood (chainsaw gas/oil + manual labor)
  • Free passive and active solar heating*

I put an asterisk on the free passive/active solar because there was the initial cost of the windows and solar collectors. Our initial investment in the active solar heating system was over $3,000 and should be taken into consideration. Installing renewable energy systems are not cheap, but I firmly believe all of our systems will pay for themselves over time. Regardless of when the systems pay for themselves, the bottom-line is that they use clean energywhich I consider priceless.

A Few Minor Changes to
If you haven't noticed, the solar heating temperatures are back on the left-hand column. They now also include the total number of Kwh's produced for the day. The other nice thing about the statistics is that they are now updated every 10 minutes thanks to our new DSL service. At some point this year, I may include a web cam with an almost live view of the's the geek in me rearing its ugly head again. But, don't expect me to allow web visitors to control the solar heating system remotely!

Internet Explorer Users: If the stats don't change by refreshing the browser, you may need to do a little tweaking with IE6. Go to Internet Options, Temporary Internet Files and click on the radio button option that reads: "Check for newer versions of stored pages...every visit to the page." This will allow the stats to load every time you refresh the page.

That's about it for now...back to the CoCoCo papers!

A beautiful sunset from the second floor deck.