South or west facing roof: which is better for solar?
South-facing produces the most total electricity. West-facing produces roughly 10–20% less, but generates it later in the day — when power is often worth more. If you are on a time-of-use tariff or a poor export rate, west can beat south financially despite making less.
Output by orientation
Northern hemisphere, as a share of the best case:
| Direction | Annual output | Character |
|---|---|---|
| South | 100% | Peaks at midday. Maximum total production. |
| South-west / south-east | 95–98% | Barely distinguishable from south. |
| West | 80–88% | Peaks late afternoon, into the evening price peak. |
| East | 80–88% | Peaks morning. Good if you use power early. |
| North | 50–70% | Rarely worth doing. |
Why west can win despite producing less
Two things decide this, and both are about when power is worth money:
- Time-of-use tariffs. Many utilities charge two to three times as much from roughly 4pm to 9pm. A west array is still producing into that window; a south array has largely finished. Fewer kWh at triple the value can beat more kWh at base rate.
- Poor export rates. Under net billing, power you use yourself is worth far more than power you export. West production lines up better with when people are home using it, so more of it gets self-consumed.
Split arrays
You do not have to choose. Panels can be split across two faces — commonly south and west — which flattens your production curve and raises self-consumption. It needs either microinverters or an inverter with multiple MPPT inputs. Which inverter suits →
Shading beats orientation, always
An unshaded west roof beats a south roof with a tree over it, comfortably. Sort out shading before agonising over compass direction. See how much sun your roof actually gets → — Google's imagery accounts for shading, so it answers the question directly rather than in theory.
What this looks like in real cities
Measured rooftop data, spanning the range from fastest to slowest payback we have found:
| City | Sun hrs/yr | Rate | Payback |
|---|---|---|---|
| Honolulu, HI | 1,787 | 42.1¢ | 3.1 yrs |
| Baltimore County, MD | 1,468 | 18.3¢ | 8.8 yrs |
| Rome, GA | 1,552 | 14.1¢ | 10.9 yrs |
| Mansfield, East Midlands | 1,000 | 26.1¢ | 12.9 yrs |
| Gatineau, QC | 1,291 | 7.9¢ | 33.3 yrs |
Frequently asked
Can I put solar on a north-facing roof?
In the northern hemisphere it is the weakest aspect and rarely worth using on its own. If it is your only option, expect a noticeably longer payback and check the numbers hard. Combining it with east or west sections usually makes more sense than relying on north alone.
Is east or west better?
West usually edges it where afternoon electricity is worth more, or where air conditioning drives evening demand, because output arrives closer to peak use. East produces earlier in the day. Both lose only modestly against south, which is why single-aspect east or west roofs remain well worth doing.
What roof pitch is best for solar?
Roughly 30 to 40 degrees suits most mid-latitude locations, but pitch matters less than people expect. Anything between about 15 and 50 degrees performs within a few percent of optimum. Orientation and shading both affect output considerably more than getting the tilt angle exactly right does.
Related guides
General information, updated 2026-08-22. Not financial, tax or engineering advice.