We turned the system live and started generating power. Both my wife and I were monitoring the system, looking for usage each day, trying to gauge our investment and ROI. It was an interesting process.


The estimate for each day of February was 41.65kWh. The first day we only generated 11.75kWh, which felt low, but it was cloudy and winter. We weren’t too concerned. The second day ended up with 46.77kWh and then 71.24kWh the third.

I felt confident that we’d sized the system well and their estimates were conservative. I started to track the production in a database, loading in the data from the monitoring system. I could download files, so I did that for Feb and wrote a little code to track the actual electricity against the estimates.

We ended up ahead of the game in Feb with these numbers, for Feb 23-28:

  • estimate: 249.9 kWh
  • actual: 340.8 kWh
  • surplus: 90.8 kWh

A great start.


March started out well for our solar system. The first couple days we were generating over 60KwH with our estimate for March being about 44kWh. It felt like we were going to be making money with the system.

Then cold weather hit. I traveled to the UK and while I was gone, we had some really cold days, single digits in the F scale. I was remotely watching the system, and saw a number of days where we had single digits of kWh production. I chatted with my wife and learned there were cloudy, snowy days.

Throughout the month, we had some good days and would have a surplus of 20-30kWh for a few days, then clouds and some days where we were below the estimate. I watched things slowly catching up, but not quite getting there. We ended the month slightly negative:

  • estimate: 1362.76 kWh
  • actual: 1331.8490 kWh
  • surplus: -30.91 kWh

Close, but a couple cloud days at the end of the month prevented us from catching up. Still, a pretty good estimate.

For the two months, we were about a day and a half up on the surplus side. It will be interested to see how this goes over time.

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