Strategically, I do NOT recommend the "free" solar panels. You have become a landlord to an electricity producer, but you're on the hook for their profits. so you have to pay for removal/install when you maintain the roof, you have to pay to trim trees, and their economic investment is attached to your home even if you sell it. the lien thing is lame.
also, however you do it, you want a good roof before the install. and you may need to manage trees that otherwise could keep growing. these might not line up with your homeowner priorities, or affect your economic question.
Economically, the question is about 'cost up front' vs 'eventual savings'. in my area the tipping point is around $85/mo. Below that you never get your money back, at $85 it just pays off by the time you need to replace panels, above that you start to save over the life of the system. this often aligns with property values, because cheap real estate means your electricity is probably made closer and thus costs less (so the wealthiest homeowners see the most obvious tradeoffs, and the poorest areas sometimes get the power so cheap that it's not worth solarizing). also, the biggest electrical users have the biggest savings. for me it doesn't really pay off right now, but if we buy 1-2 electrical cars, or electrify more of our home, it surely would.
BIG NOTE- all this math is based on a grid connected system, so there’s projections based on buy/sell prices, never certain. EDIT- for an example, see next comment.
Two magic factors:
-batteries are becoming more affordable, and have major benefits. let you shrink your panel cost, and take you away from the buy/sell disparity of on-grid systems (your extra electricity is credited at wholesale, but when the sun doesn't shine you're buying at retail, so you need to produce around 3W for every 1W that you buy; batteries are a bit better than that ratio). Plus you're fully independent and self-sustaining and zombie-proof.
-electrical prices are gonna keep climbing, and probably, faster and faster. the utilities are just now realizing their grid is a fire hazard, so rate-payers have a GIANT unmet burden to repair/replace the entire grid backbone. plus, usage keeps going up so we need to build new plants, but they're gonna cost MUCH more than old plants, so cost will surely hurt more in the future, even if it doesn't hurt now.
Environmentally, aside from the economic questions, the carbon benefits of solar are clear. production of batteries/panels is becoming cleaner and cleaner, but it's already MUCH cleaner than production of fossil fuels (more or less every way you measure it). many early adopters installed solar for these reasons alone, but the economics is more universally compelling for most of us.
Oh. panels are also made in the USA, but like all electronics you'll probably pay a bit more if you want domestic. American panels are pretty competitive, but not necessarily better.
