Housing & Mortgage
The Complex World of Rooftop Solar Panels Made Simple
An online tool helps calculate sunshine, power prices and more
If you’re among those contemplating your personal carbon footprint of late, and have already traded in the Nissan Armada (14 mpg overall) for a Toyota Prius (50 or so mpg), your next move may be rooftop solar panels.
A solar system can largely free you from buying your local utility’s power, which may derive from carbon-heavy coal, oil or gas. But before jumping in, you have some homework to do.
These systems are expensive to install, often running $20,000 or more, and it will take years before you recoup your investment.
If you search on the internet, you’ll find plenty of contractors happy to give you a call this very moment to discuss putting in solar panels. Unless you like getting the hard sell, that’s not where you want to start.
Your first step is to figure out if solar power even makes sense for you. I’ll show you a handy online tool that will do most of the work. But you also want to understand what’s important. In general, the economics of solar panels are dependent on four factors:
Your local cost of electricity Due to varying fuel sources, state utility regulation and other factors, that could be a relatively cheap 8 cents a kilowatt hour in Louisiana, Washington state or Texas, or a costly 17 cents in California and New Hampshire. The higher the price, in theory the more sense relying on your own solar panels should make.
How much sun you get (see below).
Whether your local utility is compelled to buy your (excess) power. “Net metering” is mandated in at least 34 states, Washington, D.C., and Puerto Rico. On this site you can drill down to see local solar incentives and regulations, too.
The level of solar credits in your state This will help determine how many years of electric bill savings it will take to pay off your rooftop solar installation. Gloomy Massachusetts, for example, has a payback period of just six years, while sunny Louisiana’s payback period is 21 years. California, which accounts for nearly half of U.S. solar installations, has an eight-year payback period. Many installations come with a 20-year guarantee, something to keep in mind.
It’s a lot to ponder. Luckily, there’s a free online tool from Google called Project Sunroof that can look at your roof via satellite and figure out how solar-viable you are, taking into account state-specific factors.
First, click on the site’s Explore Your Area link. It gives you a snapshot of your town, including the percentage of buildings that are solar-viable, the total electrical generating capacity and the average roof space.
In the northern New Jersey town where I live, 62% of the buildings are viable for solar power, according to Google. By comparison, 94% of the buildings are viable in sunny San Diego, the town where I grew up.
Now it’s time to look at your house. Go back to the Project Sunroof home page and punch in your home address. When I did that with my house, it told me I get 1,404 hours of usable sunlight per year. And that I have 1,269 square feet on my roof for solar panels, after taking into account obstacles like chimneys and shade trees near the house. Half of my roof faces toward the south, the best direction for solar power in the Northern Hemisphere.
Google doesn’t know my power usage, so it makes a rough estimate of savings. I look at my bills, decide we’re using about 25% more power than the estimate (ouch!), and enter that number instead. Google tells me a solar power system will cost $18,000 upfront after federal and state incentives, and it will take nine years to recoup that investment through power savings. But if I keep the system for 20 years, I will save $26,000 overall.
What if you can’t afford that hefty upfront investment? Google also estimates the savings for borrowing money to install a solar system versus leasing one. If I borrow, I will save $11,000 over 20 years; if I lease a system, I will save $8,000.
Leasing can cause additional complications if you sell the house. You may have to buy out the lease or transfer it to the new owner – if they’ll go along with that – to complete the sale.
Buying one outright seems the way to go. Will I take the plunge and install solar panels on our house? Doubtful. Solar systems only make sense if you’re going to be in a house for a long time. I don’t think we’re going to be in this house for 20 years; I’m not even sure we’ll be here nine more years to recoup the upfront investment.
And what if we have to replace the roof during that time? Then we’d have to pay thousands extra to have our solar systems removed and reinstalled.
The solar panel industry will tell you that installing a system will lift the value of your house. Maybe. Maybe not. A solar system may be a big draw for certain buyers, but other buyers may prefer a plain old roof. Bottom line: You should figure out if the solar system makes sense for you, not the next owner of the house.
After you’ve decided to go ahead with a solar system, you have to find a contractor you can trust. It is a big piece of work that has to be custom-fitted for your roof.
One of the biggest reasons that people install solar systems is that they see neighbors installing one. So start your research on a contractor by talking to some neighbors who have installed panels. How much did it cost them? Were they happy with the contractor? Are they saving as much money as promised? Make a list of contractors with good recommendations.
Now, go to the internet. The North American Board of Certified Energy Practitioners provides training and certification for solar installers and compiles reviews. Here is a website that gives you a list of solar installers in your area, cost estimates, and reviews of their work.
With much of the economy shuttered because of the coronavirus health crisis, now may be a good time to get a good deal when contractors start installing solar systems again. Bargain hard.