Rooftop solar is more expensive than people think. You need to attach the solar panel to the roof, and roofs really, really want to leak. You also need to change all of this every 15-25 years when the roof needs a new cover.
Granted the are costs that are often overlooked but that can also be mitigated by choosing installers with a good track record and offer a good warranty on their work, not whoever shows up on your doorstep, and by investing in better roofing materials.
The solar panels should still be productive after 25-30 years even if they're less efficient, and they should have paid for themselves by then. If you're like me, at installation time, the roof was overdue for maintenance anyway.
It's very unlikely for a solar company, whether an installer or manufacturer, to last 25 or 30 years. I worked in equipment sales and our suppliers would routinely go out of business or be on the verge of bankruptcy. We'd advertise warranty insurance and reinsurance because it was assumed that the company wouldn't be there that long from now.
If you just have modules (the panels themselves) on the roof that long you'd probably be okay, but if you have microinverters or power optimizers under them, those power electronics have a finite lifespan and will eventually die. Or if a single module wired in series goes bad, you'd still have roof work to do.
It's not just install and forget. It's install and pray you don't have to do too much work too soon...
(Edit: Ideally, these systems would pay for themselves in a few years. As long as that happens before they die, you'd still come out ahead. But that's not always the case. My last company got sued because the stuff we made kept failing -- it was in the news, so no company secrets there. One of our major installers also went bankrupt. Depending on who you ask, our equipment may or may not have been at fault.)
Yeah, this is one of the worst aspects of residential solar, IMO. Workmanship and labor warranties are fragile at best, and the cost to do seemingly basic things is not insignificant.
Lose a couple of panels near the middle of an array due to a power optimizer after a few years and you might end up debating whether it is even worth fixing it. That isn't so bad in itself, but it also might completely mess up your financial return estimates.
Yeah. One of the companies I worked for actually sold mostly to the DIY crowd, and I've done a few installs myself. It's not very hard -- most of it just plug and play, and even the roof entry points can be easy if you have the right flashings. (You would need an electrician to do the final approval and connection in many jurisdictions, though.)
That is to say, it might not be a bad idea to pick up a few spares when you buy a system, and learn to replace broken modules or power electronics on the roof yourself if you need to and the company no longer exists. Just a thought.
Glad you asked! There's a few ways I know... mix and match as you see fit!
1) 4-6 hours, free: Volunteer with Grid Alternatives (https://gridalternatives.org/get-involved/volunteer), a nationwide (well, several states) nonprofit that donates and installs surplus solar for needy families. You get hands-on installation experience with a crew.
3) 18-40 hours, few hundred dollars: A NABCEP prep course (https://coursecatalog.nabcep.org/exam-courses) is probably the best way short of an apprenticeship to learn to do this the right way. The North American Board of Certified Energy Practitioners gives (optional but thorough and helpful) solar installation and design certifications. Anyone can take the courses, even if you don't want to get the cert. (I did that just for my own knowledge, while working as a web dev for a solar company). Make sure whichever class you take has a mix of both theory and hands-on practice with real equipment.
4) A few months, more expensive: See if your local university or community college has cheap or auditable (drop in for no credit) courses you can take. Mine had environmental engineering and sustainability courses that included hands-on solar design and installs.
Please note that whatever you choose, in most areas it will NOT be legal to finish your install without an electrician (assuming a grid-tied system connected to your local power utility, vs a standalone battery-backed up off-grid system). You can do most of the work yourself though (great excuse for a pizza party on the roof with friends) but don't actually hook it up / turn it on without a proper permit and electrician inspection. Still, this saves a bunch of money over a fully professional install, and this way you also intimately know the equipment and labor standards better.
Edit: Oh, by the way, some solar resellers (like my former employer above) will help you design the equipment and sell it/ship it to you direct, making it that much easier (you don't have to worry about all the electrical details as much, unless you like that sort of thing... you just have to install what they give you).
I think these days there are also some online design sites (OpenSolar, Helioscope, Aurora, SolarEdge, etc.), but I think those are tailored towards industry professionals and not homeowners. Still, they might be helpful if you want to sign up and play around with a mock roof layout with real equipment connections.
