First 12 Month Legacy House Energy Results

The first 12 month’s energy consumption and cost numbers are tallied. While I was a little disappointed with the raw percentage solar, the projected annual cost came in below that expected for the house. The HERS (1) estimate was $950, and we ended up at $1058.67. But — (and BIG but) that annual cost includes one year of driving our electric car. Because the HERS calculations on our basis document do not include a car, as nearly as I can figure we are doing better than expected on total building energy useage, which I really thought we would. The data is below.

The spreadsheet above shows that winter energy consumption is higher, and that central Ohio is a cloudy place during fall and winter. No big surprise on either point. We had originally planned for 24 solar panels, and that might have been a better choice, but we thought we’d wait and see how things panned out. I think we’ll wait another year before putting panels on the main house (just on the garage, now). If we do that we’ll probably go to 28.

We have made some other little changes that may show up in the next 12 months. The hybrid water heater has recently been switched from hybrid operation to heat pump only operation. We see no difference in hot water availability, and that should reduce power use. We have also switched to a renewable power generation supplier. That lowered supply costs a bit and makes us totally renewable.


Edit: Revised spreadsheet to correct % solar numbers (increased), and eliminate electric car estimate. The car will be another topic. 8/15/2020