My Tesla Solar Performance 2020 ROI Analysis

January 24, 2021

Now that 2020 is done and over (thankfully), those of you that have been following along on My Tesla Journey are probably wondering how my first full year ROI turned out for my solar decision. At the end of My Tesla Journey Part 2, I listed out the following variables that ultimately influenced my decision:

  • Provided I can get as close to net-zero this should be a win-win. $232.49/month is less than my $251.19/monthly average electric bill from 2018.
  • Electric rates can go up over time.
  • Zillow did a study and found that homes with solar panels sell for 4.1% more than homes without. This means that if I do have a balance left, it will more than likely be covered by my house price increase. I will have an advantage against similar houses without solar. Also being able to sell the house as net-zero means that a buyer can now spend $251/month more on a larger mortgage (or other stuff).
  • Offset from not buying gas. My wife averaged about 16K miles per year on the Odyssey. I approximated that we spent about $3K/year or $250/month on gas (16,000 miles/17.5 mile/gallon * $3.25/gallon = $2971.43). Now that the house was going to be powering the car, this amount alone could justify the cost of solar (although the car is only going to consume a fraction of what the solar system will produce).

This (Part 2) blog was written when we only had 1 Tesla, so it did not factor in the gas for a second vehicle. I liked my wife’s Tesla so much that I ended up buying a Model 3 Performance in August of 2019 and took delivery in September 2019. So for 2020, we had 2 electric cars to charge. Let’s crunch some more numbers and see if I made the right financial decision for going solar.

First, it is worth pointing out that Tesla estimated my yearly production to be 21,018 kWh. My actual production was 20,880 kWh, which is only off by 138 kWh – not bad! See My Tesla Solar Performance 2020 for details on my system’s performance.

2020 was indeed a strange year. We both drove less, but the who family was home a lot more. It was also hot in Phoenix, one of the hottest years on record. With everyone home, I needed to keep the house cooler than I normally do when the kids are in school. To keep the comparison simple, my electricity costs were the following:
Solar loan: $3000 (I pay $250 per month which is what my average monthly electric bill was prior to solar, but my loan payment is actually only $233 per month)
APS electric bill: $463 (includes the credit that rolls over to 2021)
Actual Costs Total: $3463

Estimated costs based on previous cars, mileage driven in 2020 and electricity consumption costs from 2018:
The following gas approximation is based on the mileage we actually drove in 2020, but at the previous vehicle’s estimated MPG:
Her car: 7930 miles/17.5 MPG * $3.25 = $1473
My car: 6371 miles/20 MPG * $3.25 = $1035

Previous APS yearly total: $3014 ($251.19/month average for 2018)
Estimated Costs Total: $5522

In summary, by switching to electric cars and adding solar, I estimate that I have saved $2059 ($5522 – $3463) the first year. Also, this does not even factor in maintenance costs (in which I spent a total of $25.99 on each car to have the tires rotated at Costco). My savings would have been even greater had I purchased after the 20% price reduction Tesla announced in June of 2020, and I would have gotten close to the 16 kW system that I originally wanted based on the 340 watt panels. If you have any questions, please leave me a comment below or feel free to reach me on Twitter.

So what are you waiting for? If you find this information useful and are looking to order Tesla Solar or a Tesla Auto, please use my referral code to place your order to get a $100 solar award (currently) when your system is activated or 1000 Supercharger miles (currently) for a car purchase. Tesla Solar recently announced on June 19, 2020 a 20% price reduction (The Lowest Price for Home Solar) and they also now use the 340 watt panels (up from the 315 watt panels that I have). This will cover the $99 down, making it zero out of pocket initial cost when financed.

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