The Legacy House got its U.S. Department of Energy Zero Energy Ready Home (1) certification (dated August 1, 2019). That’s a recognition of the quality of the work done to build an efficient home. A standard new home has an HERS Index (2) rating of 100 or thereabouts. The Legacy House came in at 17. Lower is better, of course.
The certificate projects an annual energy cost of $950 and annual electricity savings of 27,934 kWh. Estimated CO2 reduction is 24.9 tons. We will watch it and see how accurate this information is.
We have four months’ data to give us some idea how the Legacy House solar plant, seen above just after installation, is working.
May 2019 — $46.48, 731 kWh delivered, 416 kWh to grid, 315 kWh net. June 2019 — $20.40, 617 kWh delivered, 544 kWh to grid, 73 kWh net. July 2019 — $9.50, 488 kWh delivered, 536 kWh to grid, -48 kWh net. August 2019 — $16.48, 619 kWh delivered, 577 kWh to grid, 41 kWh net.
It appears that we are getting a bit less than 85% of our power from the garage roof panels. That’s great, but a bit more than we really want. Unless one builds off-grid, AEP Ohio expects net-metering users like us to buy some power to pay for grid maintenance. That’s fine.
Keep in mind that the numbers above relate to the house and the electric car in the garage.