If you’re considering solar, you can find solar installers via EnergySage (referral link) and get a $25 Amazon Gift Card when you go solar. I found the installer that we ultimately used, which was a lot better option than using one of the many door-to-door solicitors that show up in the neighborhood.
Perspective on our Placement for Solar
Our house is in Cantonment, FL, which is at 30.6°N latitude. If you’ve been to the Florida beaches in early spring after spending the winter somewhere [reasonably north of Florida], your skin is well aware of how much more intense the sun is. Aside from cities in Florida, only San Antonio, Austin, and Houston in Texas, New Orleans in Louisiana, and Mobile in Alabama are further south than we are.
The back roof of our house also points pretty much due south, and as you can see, the south panels are the most productive through the day:
Specs on our system
We have 48 290W panels with micro inverters on each panel so that each panel is monitorable. They were definitely more expensive this way and based on outage turnaround time that prompted me to write a script to monitor, it would probably cost $200-400 worth of lost production waiting to fix the problem. Given that that’s about 1% of the cost of the solar array and the price differential was easily 10-20% the extra “observability” into individual panels seems to be too steep a premium (but the more traditional panels also had the aluminum storm door look versus the fancy new ones!)
We also have a solar collector for hot water (that also requires that we stick with electric for the water heater.) The tank is 80 gallons, with half of the tank always heated by electric as a backup. The solar collector will heat up the other half by circulating to between the tank and the roof.
Unlike the photovoltaic panels, the solar part of the water heater doesn’t produce usable hot water on its own in the winter months. It will, however, warm up enough during the day to assist in heating by supplying 80-90℉ water to the electric side. This will be offset by the fact that if it gets near or below freezing, the water in the tank has to circulate to the collector on the roof so that it doesn’t freeze. That’s not a huge problem in the winter here, because it collects enough warm water on those days to get through the night… but for places that get significant snows *plus* power outages, that could be a recipe for disaster.
At the time, the solar installs were financed at 100%, with the option of either financing it all at a high single digit rate or 30% down via 12 months same as cash in anticipation of the tax credit money and 70% on a 12 year loan at low single digit APR. The full financing at the higher rate was pretty much like borrowing money on your future utility bills at a high interest rate in order to keep the tax credit.
87% of the solar loan we have goes to paying off the solar panels (vs. the water heater), so about $235/month.
Return on Investment
According to our energy bills, the charge for electricity is about $0.14/kWh. This includes fees that move up and down in more of a step-like manner, but not fixed charges. At 18MWh/year that means we’re generating about $210/month in electricity vs. the $235/month payment. There are two things to keep in mind: First, the payments only last 12 years, but the solar panels are supposed to be at at least 80% efficiency for 20. Second, the return on investment improves if the price of energy increases faster than the efficiency of the solar cells decays.
Solar is not a no brainer. If you want to do it for the environment, that might put you over the top in terms of return on investment. The solar water heater (left out of this post) is a lot harder to measure, but you probably want to live in a place that doesn’t get near freezing in the winter.