Solar Panel Calculator for Portland, OR
Estimate the cost, savings and payback of solar panels in Portland, OR, using local NREL sunshine data, Oregon prices and electricity rates.
Your result
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Portland gets about 4.09 peak sun hours a day on a south-facing roof, so each kW of panels makes about 1,120 kWh a year. That ranks #105 of the 111 cities on this site. Output peaks in Jul and is lowest in Dec.
Sunshine in Portland by month
What an 8 kW system makes in Portland
| Month | Sun hours a day | Output | Bill savings |
|---|---|---|---|
| Jan | 1.42 | 280 kWh | $43 |
| Feb | 2.77 | 496 kWh | $77 |
| Mar | 3.32 | 640 kWh | $99 |
| Apr | 5.05 | 920 kWh | $142 |
| May | 5.70 | 1,056 kWh | $163 |
| Jun | 5.95 | 1,048 kWh | $162 |
| Jul | 7.03 | 1,256 kWh | $194 |
| Aug | 6.23 | 1,112 kWh | $172 |
| Sep | 5.36 | 944 kWh | $146 |
| Oct | 3.18 | 608 kWh | $94 |
| Nov | 1.79 | 336 kWh | $52 |
| Dec | 1.30 | 264 kWh | $41 |
| Year | 4.09 | 8,960 kWh | $1,385 |
Savings at 15.46¢ per kWh (Oregon average), with every kWh credited at that price.
Cost and payback by system size
At $2.40 per watt, the Oregon average, before incentives.
| System | Cost | Year 1 savings | Payback | 25-yr gain |
|---|---|---|---|---|
| 4 kW | $9,600 | $693 | 14.3 yrs | $6,715 |
| 6 kW | $14,400 | $1,039 | 14.3 yrs | $10,073 |
| 8 kW | $19,200 | $1,385 | 14.3 yrs | $13,430 |
| 10 kW | $24,000 | $1,732 | 14.3 yrs | $16,788 |
| 12 kW | $28,800 | $2,078 | 14.3 yrs | $20,145 |
How many panels you need in Portland
| Monthly use | System | 400 W panels |
|---|---|---|
| 500 kWh | 5.36 kW | 14 |
| 750 kWh | 8.04 kW | 21 |
| 1,000 kWh | 10.71 kW | 27 |
| 1,500 kWh | 16.07 kW | 41 |
| 2,000 kWh | 21.43 kW | 54 |
Covering 100% of a year's use at 1,120 kWh per kW.
Common questions
Is solar worth it in Portland?
At local averages an 8 kW system costs about $19,200 before incentives, saves about $1,385 in its first year and pays back in about 14.3 years.
How many peak sun hours does Portland get?
About 4.09 a day over the year on a south-facing roof at 20°, from 1.3 in Dec to 7.0 in Jul, according to NREL's PVWatts model.
How much does a 1 kW solar system produce in Portland?
About 1,120 kWh a year, or 93 kWh a month on average.
Is there a federal solar tax credit?
Not for homeowners who buy their system. The 30% Residential Clean Energy Credit ended for systems installed after December 31, 2025.
Sources
- NREL PVWatts V8 API (south-facing, 20° tilt, 14% losses, typical-year weather): https://developer.nlr.gov/docs/solar/pvwatts/v8/
- EnergySage, Solar panel cost by state (updated November 6, 2026): https://www.energysage.com/local-data/solar-panel-cost/
- U.S. EIA, Electric Power Monthly, Table 5.6.B (residential price, Jan–Aug 2026): https://www.eia.gov/electricity/monthly/epm_table_grapher.php?t=epmt_5_6_b