Chart showing monthly usage, generation, net and hdd
Chart showing monthly usage, generation, net and hdd

We used 498 kWh and generated 615 kWh for a net surplus of 117 kWh in November. This is our ninth consecutive surplus month. We’ve generated a surplus of 3,622 kWh so far this year, guaranteeing we’ll be net positive for our first year of operation.

The month proved to be sunnier than average. We generated about 63% more than predicted, despite the fact that it was about 12% cooler than average for the month. Usage was up 19% over the previous month. Lot’s of guests, cooking and laundry for the Thanksgiving weekend period.

We used 46 kWH for heat. That’s about 55 watts per HDD. That accounts for 9% of the month’s total usage. Compare that to hot water which used 38% of the energy for the month. We used 61.7 gallons of water per day, down about 9% from the previous month.

I’ve been updating some of the data reporting measures. This month I’ve moved to reporting all heating degree days at a base temperature of 65 degrees rather than 68. This should make it easier to compare performance to other homes that use 65 as a base temperature.

All values in kWh (except HDD).

  1. January values based on meter reads.
  2. February values based on TED data.
  3. Heating Degree Days (a measure of how many outside degrees in a day it is below a target inside temperature)
  4. Calculated from our HOBO outdoor weather monitor hourly data, unless otherwise noted.
  5. January HDD data downloaded from degreedays.net, Station ID: KALB (Albany International Airport).
  6. March values based on meter reads. (TED died March 1st, eMonitor installed March 16, 2012)
  7. Values based on eMonitor data.
Month Solar PV Usage Net usage or (surplus) Avg. daily usage HDD 3,4
Jan 1 369 873 504 28.2 1,125 5
Feb 2 597 666 69 23.0 957
Mar 6 860 515 (345) 16.6 619
Apr 7 925 378 (538) 12.9 535
May 867 309 (558) 10.0 170
Jun 939 325 (614) 10.8 97
Jul 970 319 (651) 10.3 17
Aug 1,018 315 (703) 10.2 31
Sep 883 292 (591) 9.7 168
Oct 511 433 (78) 14.0 357
Nov 615 498 (117) 16.5 830

You can see heat maps and detailed charts of temperature and electrical usage at netplusdesign.com. View solar, usage, net usage, temperatures and HDD for all of February and circuit-level data for 16 days in March and the full months of April through November.