South-Facing or West-Facing Panels: Which Wins in 2026?

For decades, installers used a simple rule. Point the panels south, tilt them at roughly your latitude, and forget about it. That rule was correct under traditional net metering, where every kilowatt-hour you sent to the grid was worth exactly what you paid to buy one back. Under that math, you wanted the largest total annual production, which means south.

Things have changed. As more solar has come online, utilities and regulators have shifted toward time-of-use pricing and away from one-for-one net metering. California's NEM 3.0, passed in 2023, is the most aggressive version, but versions of the same idea are spreading. Hawaii has been there for years. Arizona, Nevada, and parts of the Northeast are moving in the same direction.

Under time-of-use rates, a kilowatt-hour exported at 1 p.m. on a sunny April afternoon is worth almost nothing, because the grid is awash in solar at that hour. The same kilowatt-hour exported at 6 p.m. on a hot August evening can be worth four or five times as much, because that is when air conditioners are running and utility-scale solar is fading.

West-facing panels produce less total energy over a year, usually about 10% to 15% less than south-facing, but their production curve is shifted later in the day. A west-facing array peaks around 4 p.m. instead of 12 p.m. If your utility pays you more for that late-afternoon power, the lower total production is more than offset by higher value per kilowatt-hour.

Here is a concrete example. A south-facing 8 kilowatt system in Sacramento under NEM 3.0 might produce 12,800 kilowatt-hours a year worth roughly $1,150 in bill offset. The same 8 kilowatt array facing west produces about 11,200 kilowatt-hours worth roughly $1,380. The west-facing array is the better financial decision despite producing less power.

Battery storage scrambles this calculation. If you have a battery, you can produce in the middle of the day, store, and export later. South-facing returns to being the right answer because total annual production is back to being what matters. This is why so many California installers now sell solar-plus-battery as a package rather than panels alone.

If you have a roof that does not face south or west cleanly, all is not lost. East-facing panels lose about the same amount of production as west-facing but shift the curve earlier, which has gotten more valuable for homeowners who run their dishwasher and laundry in the morning. North-facing is still a bad idea in the northern hemisphere, full stop.

When evaluating a quote, ask your installer to show you the production-weighted value of energy, not just the kilowatt-hours. A good design tool like Aurora or Helioscope can do this calculation in about five minutes. If the installer cannot or will not show it to you, that is information about the installer.