If you’re collecting solar quotes this fall, the installer you call first could decide whether your system costs $18,500 or $48,500.
Same size system. Same country. Same year.
That’s not a sales pitch from either side. It comes from Berkeley Lab, the Energy Department lab whose solar price data runs back more than two decades.
The spread nobody quotes you
In August, Berkeley Lab published its 2026 data update, covering about 5.3 million systems installed through the end of 2025. One slide ranks the 100 busiest residential installers by the median price their customers paid.
The cheapest typical price was $2.40 a watt. The most expensive was $6.30.
Roughly 60% of those installers had a median under $4 a watt. Almost a quarter came in under $3. About one in ten charged a typical price over $5.
The median home system in 2025 was 7.7 kW, or 7,700 watts. Do the multiplication. At $2.40 a watt, that’s about $18,500. At $6.30, about $48,500. The gap is roughly $30,000 for the same amount of roof power.
Here’s the catch for anyone who trusts one friendly salesperson. Berkeley Lab also found prices swing inside a single company, typically by $1 to $2 a watt between its cheaper and pricier jobs. On 7,700 watts, that’s $7,700 to $15,400 riding on how well you negotiate with the same outfit.
Why it bites harder now
The federal residential solar credit is gone, as we covered when it died. There’s no 30% cushion hiding an overpriced quote anymore. Every dollar above the going rate comes straight out of your payback.
And how you pay matters. The median 2025 price was $3.00 a watt for known cash purchases and $4.50 for known loan-financed systems. Berkeley Lab says loan origination fees rolled into the price may explain part of that. We’ve shown how a 1.99% solar loan can hide $5,700 the same way.
Verdict: one quote is dumb math.
The move
Get at least three written quotes before you sign anything. For each one, take the total price before incentives and divide by the system size in watts. Anything near $3 a watt is in the cheap half of the market. Anything over $5 needs a reason you can see on paper, such as a battery, a hard roof, or premium equipment.
Ask every installer for the cash price, even if you plan to borrow. Then run each quote through our solar ROI calculator and see which payback you can live with. Our best solar picks page has more on what to compare.
If a salesperson won’t put a per-watt price in writing, that’s your answer.
The detail
Berkeley Lab’s prices are the up-front amount reported by the owner, before incentives, in 2025 dollars. They cover host-owned systems only, so leases and power purchase agreements aren’t in them. Cash and loan medians come from the roughly 45% of host-owned systems where the financing type could be identified with confidence. The lab cautions that installer-level gaps can reflect business models, local markets, and differences in how installers report prices. Overall residential prices fell $0.50 a watt from 2024 in inflation-adjusted terms.
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