How much will solar panels produce in Rennes?
A 6 kWp system facing south at 35° tilt in Rennes produces about 7,202 kWh a year. In a weak year that is 6,022 kWh, in a good one 8,383 kWh — 1,200 kWh per kWp.
That’s about 153% of a typical home’s yearly use (4,700 kWh).
Based on 2014–2023 satellite weather data
Production by month
kWh per month
A typical day in July
The sunniest month in Rennes. Output peaks around 11:00 solar time, at about 3.3 kWh in the best hour.
Month by month
| Month | Weak year, kWh | Typical year, kWh | Good year, kWh |
|---|---|---|---|
| January | 214 | 278 | 341 |
| February | 334 | 417 | 501 |
| March | 474 | 613 | 751 |
| April | 617 | 761 | 904 |
| May | 642 | 802 | 962 |
| June | 630 | 818 | 1,005 |
| July | 652 | 824 | 996 |
| August | 631 | 781 | 932 |
| September | 543 | 678 | 812 |
| October | 390 | 491 | 592 |
| November | 289 | 360 | 431 |
| December | 194 | 250 | 306 |
| Year | 6,022 | 7,202 | 8,383 |
The months don’t add up exactly to the yearly figure, because each one is the typical value across many years.
Common questions
How much do solar panels produce in winter in Rennes?
From November to February the system produces about 1,304 kWh, which is 18% of the year. The weakest month (December) gives roughly 250 kWh.
Is an east-west roof worth it in Rennes?
An east-west system typically produces 10–25% less per kWp than one facing south, but spreads production more evenly through the day. The exact difference depends on tilt and shading.
Ground mount or roof in Rennes?
A ground mount can be tilted and aimed freely, which can add some yield, but it costs more and needs space. Compare both for your own plot.
Your roof is not an average roof
Set your own tilt, direction, shading and inverter limit and get a range for your address.
Calculate for my roofClimate data: Photovoltaic Geographical Information System (PVGIS) — European Commission, Joint Research Centre