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Comment by neap24 | Hacker News Reader

I really don't understand the obsession with homeowner solar. The financing schemes are crazy (companies owning part of your roof, renting the equipment, etc.). The only way to do it properly is to either pay someone else cash or to do it yourself. But then, even then, when I did my ROI calculation a few months ago (I live in a small house that is very efficient as-is), I was looking at 10-15 years before I'd see any savings. Then, I learned that the lifespan on some of the equipment and panels may only be 20 years. Granted, replacing them beats the cost of the original install and permitting process, but now I have something else in addition to shingles on my roof that needs replaced after a couple of decades.

It just doesn't make sense to me to mess with it now. As others have mentioned, pushing for grid solar/nuclear/other clean energy is really the only way to do this efficiently. Then I won't have a mass of ugly panels stuck on my roof.

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The ROI can change a lot depending on your particular circumstances, though. If you live in a not-so-sunny place with minimal electricity use, a 10-15 year ROI isn't unreasonable. But if you live in a sunny place and pay a lot for HVAC or an electric car, the payback can be much shorter (sometimes 5 to 7 years, especially if you self-install). Time-of-use billing can also dramatically change the numbers, depending on your state/electric utility and household usage habits -- sometimes even to the point where you can use a battery to play electricity arbitrage, buying/generating low and selling back high (if your area allows such a scheme).

Electricity prices are expected to keep going up too. But there is also uncertainty in how utilities will renegotiate (or else grandfather in) existing solar ratepayers. California's solar pricing schemes have changed a lot just in the last decade as they went from minimal solar to solar oversaturation (the grid couldn't keep pace with the # of installs).

At the end of the day, for some homeowners, solar is a no-brainer. For others, it doesn't make sense. It totally depends... it isn't an automatic win, but also not something that should be categorically written off. It's worth investigating, especially for new constructions that are heavily electrified (i.e. use electricity for heating/cooling/cooking instead of gas or other fuels).

But agreed that grid-scale makes more sense, combined with other power technologies.

One minor nitpick: It's unlikely the PV modules (solar panels) themselves will fail in 20 years; you'll more likely have to replace your inverter before the cells themselves break. Sometimes those inverters are string inverters in your house (no roof work needed), other times they are microinverters/power optimizers attached to the modules themselves, which would make it more complicated to replace.

Hi, I have similar calculations, but Germany has a simpler model installing 800 W solar system without any paperwork for one electricity meter. Produced but not consumed electricity is not paid for. However it covers most use cases. It worked sooo well for my colleague, that he illegally installed second 800 W system on second phase (we have here mostly 3 phase systems in Germany). I am waiting for autumn/winter to get my system cheaper off season. The savings come in second year with regular prices and in third year with current insane prices.

A) financing is crazy, don’t do it B) if the ROI doesn’t work, don’t do it.

For many people though (older / less efficient homes, larger families, more expensive electricity) it makes a lot of sense. I did a 10kw system on my last home and the break even point was 6 years. The couple with no kids that bought the house from us likely won’t have an electric bill above $0 for years…

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