The average cost of a solar panel has fallen from roughly $76 per watt in 1977 to under $0.30 per watt at the wholesale level today — a price collapse with almost no parallel in the history of manufactured goods. For homeowners, the more relevant figure is installed system cost, which dropped from around $45,000 for a typical 6 kW system in 2010 to roughly $15,000–$18,000 before incentives in 2026, according to data from the Lawrence Berkeley National Laboratory. After the 30% federal Investment Tax Credit, many households are looking at net costs closer to $10,500–$12,600.
That trajectory matters because it fundamentally changes the math on going solar. A decade ago, payback periods of 15 years or more were common in most US states. Today, the national average sits between 7 and 10 years depending on local electricity rates and sunlight hours — and in high-rate states like Massachusetts and California, paybacks under 7 years are increasingly standard. Understanding why costs fell so far so fast also helps you judge whether waiting another year or two for further savings makes sense, or whether the financial case for acting now is already compelling.
The short answer to that last question: prices have stabilised considerably since the steep drops of 2010–2020, and waiting is unlikely to produce the same dramatic savings it once did. The bigger variables now are your local electricity rate, available incentives, and how much your utility charges for grid power — factors that vary widely by state and household.
