Energy Consumption Update

The above jpeg shows a screen shot of our most recent information for our energy bills.  Click on it to get a more magnified view.

Notice the downward trend in our energy usage since we moved into the house.  Notice especially the first August when there was a peak.  After that August, I added radiant barrier insulation to the attic and from then on, there was no summer peak.  That speaks to its effectiveness even though it technically has no R value as an insulator, is paper thin, and is perforated.  Moreover, it's cheap, get some.  We usually set our thermostat to 78F in the summer, but lately we've been finding ourselves wanting to set it lower and it seems to be because the AC isn't on enough to draw all the humidity out of the air and make it seem cooler.

Since adding more than six inches of new insulation to the attic this last spring, I am wondering what the change in the bills will be.  Notice the difference between this November and last November.  There is a difference of 7 kWh per day, that is significant, though differences in weather could be to blame, I doubt all of that would be due to the weather.  The rest of the winter will bear out the differences, but I predict continued record lows.

If you look toward the upper right hand corner, you can see that I make a comparison between the average household and mine in terms of energy usage.  This doesn't account for gas and other forms of energy usage on the national numbers, but my house is almost completely electric.  Only the backup heat which comes on when it is lower than 25F outside is propane, and as you can see, I use 80 gallons or less a year.  As you can also see, right now I am using about 65% of the national average.

I also drew a comparison between the Passivhaus standard in Germany and my own energy usage.  I am running a little more than four times as much energy as my goal of a Passivhaus.  I use Passivhaus because Passive House doesn't really mean the same thing and isn't necessarily identified with the same standard.  The Passivhaus standard is very strict, it includes energy used from gas, oil, and wood, not just from electricity.

Hope this has been informational, I enjoy continued projects to try and lower the energy usage of the house.  This year as I mentioned, I added insulation, but also removed a window.  I replaced a window last year, but a single window won't show up on the stats in such a short term with little to compare to.

Happy savings,
WiredForStereo

Home Energy Consumption Update

Just got our latest electricity bill. We are up to about 31 kWh per day in a December with several cold spells, and two nights into the single digits. However, our heating system uses propane below 25 degrees F outside, so those nights are not the source of the electricity usage, the cold rest of the time is. One day, I'll figure out how to calculate the propane usage into the energy equation. It would need to be divided into every day that we heat over the whole winter. We've already used one tank this winter so far.

A gallon of propane is 91,690 BTU's = 28.87 kWh x 20 gallons per tank.

= 577.43 kWh per tank

On second thought, the tank is filled to 100 lb (accurate or not) which is 635.26 kWh worth of energy.

As you can see, if we use 3 or 4 tanks per winter, there is a much larger amount of energy being used. That's why the heat pump is so useful. If we use one kWh to heat the house, we get somewhere between 2-4 kWh of heat in the house, because the heat is being moved by, not made from electricity.

Still, pollution wise, the electricity is made largely from coal, whereas the propane has few emissions and is often a waste product from other processes. On the other hand, as I often say, I can make electricity, I can't make propane.

WiredForStereo