That $30k Solar Add-On on Your ADU: Real Line Item or a Number Somebody Made Up?

Thirty grand for two kilowatts is fifteen dollars a watt. The going rate is about three.

Break the factory number down to its unit and it gets loud. Thirty thousand dollars divided by two thousand watts is fifteen dollars per watt of solar.

A full-size rooftop system installed on a house here in Central Florida runs somewhere around three dollars a watt, all in — panels, inverter, mounting, labor, permit, the crew on your roof for a day. The factory add-on is charging you roughly five times that for a system a fraction of the size.

Now, small systems do cost more per watt than big ones. The permit, the inverter, the electrician's trip charge — those are close to fixed whether you're putting up two kilowatts or ten, so they get spread over fewer watts and the per-watt number climbs. That's real. It explains why a tiny standalone system might run four or five dollars a watt instead of three. It does not explain fifteen. Fifteen isn't a small-system penalty. It's a number with nothing underneath it but convenience.

What two kilowatts actually does — and whether it pays you back depends on your meter

Here's the part that reframes the whole line item: two kilowatts is not "the ADU runs on sunshine." On a good Florida day it makes about eight to ten kilowatt-hours. That's the fridge, the lights, a couple of TVs, the WiFi, and a small AC for a few hours. It is not the dryer, the oven, or the AC running through an August afternoon. It's a dent in the bill, not a replacement for the grid.

And whether that dent turns into money back in your pocket depends entirely on which power company reads the meter on your street. If you're on Duke Energy Florida, extra power your panels push out gets credited at the full retail rate — a dollar of power out is a dollar off your next bill. If your ADU sits in Orlando Utilities Commission territory, OUC is a municipal utility and sets its own export rate, which can be lower than what you pay to buy that same power back. Same two panels, two different payback stories, and the factory sheet doesn't ask which one you're under. You have to.

The 2026 catch nobody puts on the invoice: the math got worse, and "DIY" still needs an electrician

Two things changed the DIY-versus-buy calculation this year, and both work against the sticker.

First, the thirty percent federal solar tax credit is gone. It expired December 31, 2025, with no phase-down — it went from thirty percent to zero overnight. If you buy and own a system in 2026, there's no federal check coming back to soften it. Every quote you see, factory or otherwise, is now the actual number you pay.

Second, the thing people mean by "just DIY it" isn't fully a thing in Florida. The state does let a homeowner pull their own solar permit and act as their own contractor on a home they own — you can buy the gear, set the panels, do the parts you're allowed to do. But the statute still says a licensed electrical contractor has to handle the wiring and the tie-in to your panel. So the real version of DIY here is: you own the hardware and the sweat, and you pay a licensed electrician for the one part the state won't let you touch. That's cheaper than fifteen dollars a watt. It's not zero, and anybody who tells you it is hasn't priced the electrician's trip.

So before you sign off on any line item, find out what your lot can actually hold

The solar number is just the loudest example of a bigger thing: an ADU price sheet is full of items that only make sense once you know your specific lot, your specific utility, and whether you're in unincorporated Orange County where a program like Ready Set Orange can pre-clear a design and shave the permit dance. A 2kW package might be a fine idea in Winter Garden and a waste in Pine Hills, and no factory sheet knows the difference.

That's what the ADU Fit Check is for. Answer a few questions about your property — where it sits, what utility you're on, what you actually want the second unit to do — and you get a read on what fits before anyone hands you a spec sheet with a thirty-thousand-dollar line on it. Start with the Fit Check, then decide what solar, if any, is worth bolting on.

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