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PaperclipPerfector  2d ago (text post)   2010 thread views

Small-Scale Question Sunday for September 6, 2026

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Is rooftop solar a good investment if you're a homeowner? Thinking about an install after getting a house.

Earlier this year for my house, I estimated it at about $24k to install and then $3k/yr effective revenue. You break even at 8 years and then by the end of the life (we’ll call it 24 years for nice numbers), you’ve made 3x returns. That’s about a 4.7% interest rate, which is higher than high yield savings account equivalent, but less than you would expect from the market (though it’s untaxed since it’s avoided spending).

Some things that will make your model different:

  1. What level of sun does your property get based on weather and shade?
  2. How high are your electric prices and what is your outlook on how they will move in the future?
  3. Does your locality require utility companies to buy excess power you generate? Do you get any state-level incentives now that there’s no federal ones AFAIK? Without these my estimates would be way worse.
  4. How many of your utilities are electric vs fuel (eg gas heaters, stoves, dryers, etc)? Especially important if they don’t have to buy your excess power generation.
  5. How long do you expect to be at the property? You’ll need time to recoup the cost. If you move early and sell the house, I wouldn’t count on the buyer valuing the panels at the same amount you would.
  6. What condition is your roof in?

I decided not to do it, and it wasn’t particularly close. That rate of return is only ok and I would much rather have the liquidity. I also have a low appetite for hassle, and my experience is to count on significant home renovations to always be a hassle in one way or another. If you’re in a place with favorable weather, mostly electric utilities, expect energy prices to go up, and like the idea of self sufficiency seems like a good deal then. Panel prices will probably continue to drop but installation labor costs will probably rise. I would expect overall price to go down in the future but maybe not a lot.

$24k to install

Can you break it down. Where I live this is the cost of 130Kw solar powerplant. Give or take.

I saw that a typical residential installation is on the order of 10kW of panels and costs about $3/W installed, for $30k. I subtracted a little for some incentives and assumed something a little smaller than average, arriving at $24k. A quick google suggests $3/W is a typical residential installation cost. If you say 130kW plant costs $24k that’s $0.18/W, more than an order of magnitude cheaper. Maybe you’re somewhere muuuch cheaper, or maybe rooftop solar is just really expensive/inefficient compared to just putting them in a field.

I am not in the USA. But I assume that the costs of panels is comparable. So 30kw of panels here are 5500 eur (I could probably shave 500 if I actually bother to search, this is just first google list price). Probably put additional thousand for inverter/wiring. For 10Kw the bom is probably 3k euro?

So the bom is quite modest. And I am sure in USA won't be much more expensive. So I am just wondering where the rest of the money goes.

The US (also Canada) has really large tariffs on Chinese panels -- I haven't looked lately, but I think they would cost quite a bit more than 5500 EU here.

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