District of Columbia pays about 17.2¢ per kilowatt-hour for residential electricity and receives about 4.4 kWh per square metre per day of sunlight — 14th and 34th respectively among the 50 states and DC tracked here. Those two numbers set the ceiling on what rooftop solar returns in District of Columbia, and they point in opposite directions.
Where District of Columbia sits against the rest of the country
District of Columbia is 2.4¢/kWh above the median residential rate across this dataset (14.8¢/kWh) and 0.2 kWh/m²/day below the median insolation (4.6 kWh/m²/day). Under this site's standard assumptions, that combination puts District of Columbia 19th of 51 for modeled payback speed, at 12.8 years against a dataset median of 13.5 years.
What actually drives payback in District of Columbia
District of Columbia is rate-led: upper half of the dataset for electricity price (14th), lower half for sunlight (34th). Swap District of Columbia's sunlight for the dataset median and payback moves to 12.3 years (0.5 years of swing). Swap its electricity rate instead and payback moves to 14.5 years (1.7 years of swing). The rate swap is the larger of the two, so what a kilowatt-hour costs is the input deciding the outcome in District of Columbia.
State incentives on record
Recorded for District of Columbia: Solar for All program (income-qualified free systems); SREC market among highest-priced in US; net metering; property tax exemption.
No federal credit is applied above (Section 25D expired 31 December 2025), and export terms often matter more than the headline rate (net metering guide).
The modeled system, in numbers
At District of Columbia's sunlight level a 7 kW array produces roughly 8,769 kWh a year, worth about $1,508 in first-year bill savings at 17.2¢/kWh against an assumed $22,400 installed cost. A ten-year payback at this sunlight level would require a residential rate of about 22.9¢/kWh, which is 5.7¢ above what District of Columbia households pay today.
States with comparable economics
District of Columbia's closest analogues by modeled payback are Delaware (13.1 years), Maryland (12.4 years), Michigan (12.3 years). They arrive there from different rate and sunlight combinations, so their incentive rows are the useful comparison.