I am beginning to acquire knowledge to assemble my first self-consumption solar kit and I have been investigating what kind of solar panels I should use for a house of approximately 50 m2 with a consumption of about 3000 kW but I am not entirely clear, I am between:

12V solar panels

60 cell solar panel

24 V solar panels

Does anyone have experience on the subject and can you advise me?

  • Will you need back-up power? The simplest, cheapest solar systems will not provide electricity when there is a grid outage. If you want backup power it will affect the answer, and also cost significantly more.
    – LShaver
    Apr 1, 2021 at 15:47
  • 3000kW is certainly wrong - you probably meant 3000W?
    – user253751
    Aug 2, 2021 at 17:09

1 Answer 1


Unless you are planning to go off-grid (which is quite stupid as energy storage is best done on an industrial scale as hydrogen stored underground, and not on a single-home scale in batteries, as batteries are very expensive), there are only two satisfactory answers to this question:

  1. If the cost of solar panels is so high that the annual yield of your investment, taking into account depreciation of the installed panels, is below that of an alternative investment such as a well-diversified stock portfolio, the best bet is to not install these panels at all. Doesn't make sense to invest in something that produces only very little yield.

  2. If the cost of the solar panels is so low that the annual yield of your investment exceeds that of other alternative investments such as a well-diversified stock portfolio, cover all suitably oriented surfaces of your roof with solar panels. In fact, if you have unused land area, you could also install even more solar panels on the ground.

So if solar panels are worth it, the amount of panels to install is determined by the amount of area you have for these panels. Better to use all of the area as opposed to using only half of the area.

My opinion is that there probably aren't very many places where the price of electricity is so high and the labor rate for installing panels is so low that solar panels would make sense on the small scale for a single home. Also, you have to consider what happens if everyone installs solar panels. Then the price of electricity becomes very dependent on sunshine, i.e. when you have the most sunshine, the price of electricity is zero due to excess production and then your panels aren't producing any revenue at all.

  • 2
    Given that this is the Sustainable Living forum, I would suggest that financials are not the only consideration for the OP
    – John M
    Jul 12, 2021 at 11:41
  • @JohnM it's not just financials, but opportunity cost. If you save money by not installing solar panels, perhaps you could invest that in an EV, a better furnace, improved insulation, etc.
    – LShaver
    Jul 14, 2021 at 14:14
  • @LShaver sure, but that is clearly not what the answerer had in mind
    – user253751
    Aug 2, 2021 at 17:10

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