What a watt actually costs
Solar is priced per watt because systems come in different sizes. At $3.75 a watt, an 8 kW system, roughly 20 panels, is $30,000 before anything is taken off. Nothing is taken off any more.
Two national figures, and why they differ
The gap between those two numbers is the most honest thing on this page. Berkeley Lab collects this data from state incentive programmes, so states that run such programmes report and states that do not are invisible. CA alone is 78% of every reported installation, and it is an expensive market, so a simple average of all systems is really CA’s price wearing a national label. This site leads with the median of the state medians instead, where each covered state counts once.
What people paid, by state
The bar shows the range the middle half of buyers landed in. A quarter paid less than the left edge and a quarter paid more than the right, which is worth remembering when you are holding a single quote and wondering whether it is fair.
Delaware at $3.18 a watt, on 1,599 installations.
California at $4.36 a watt, on 159,263 installations. That is 37% more for the same hardware.
Three numbers, three different questions
Search for the cost of solar and you will find figures from about $2.50 to about $4.50 a watt. They are not contradicting each other. They are answering different questions.
Modelled benchmarks describe what an efficient installer’s costs ought to add up to, built from the bottom: panels, inverter, racking, labour, permits, overhead, margin. They come out lowest, because they describe a well-run hypothetical company rather than the one that actually knocked on your door.
Marketplace quote averages describe what companies offer when they know they are bidding against three others on a comparison site. They come out in the middle, for the obvious reason.
Reported installed prices, which is what this site uses, describe what was written on contracts that actually closed. They come out highest. Most people do not run a competitive tender for their roof; they take a quote from someone who called them.
If you are about to buy, the third number is the one that tells you what your neighbours paid. The first tells you how much room there is in the price.
What is actually in the price
Less than you would guess is hardware. Modules themselves are a commodity and have collapsed in price over two decades. What has not fallen is everything around them: sales and customer acquisition, permitting, inspection, interconnection paperwork, scaffolding, labour, and the installer’s margin. That is why American installed prices are multiples of Australian or German ones for identical panels, and why shopping hard moves the number more than choosing a different brand of module does.
Three competing quotes beat any amount of comparing panel brands
Sales cost and margin are over a third of an installed price, and they are the part that competition removes. A single quote from whoever reached you first is how people end up in the top quarter of what their neighbours paid.
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Prices and rules change. We will tell you when they do
Berkeley Lab publishes installed prices once a year, the EIA updates electricity rates every month, and Congress changed the tax treatment of all of this in 2025. One email when something on this site actually changes, and nothing else.
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