Solar panel angles, by city
The angle that collects the most sunlight over a year depends on your latitude, and it is not the one the rule of thumb gives you. More usefully: it barely matters. Which way your roof faces matters enormously.
1,000 cities across 114 countries, each with its optimal tilt and orientation, seasonal angles, and a score for every roof.
The short version
- Face the equator. Due south in the northern hemisphere, due north in the southern. This is the decision that matters.
- Tilt is forgiving. Anywhere within about 15° of optimal costs you a couple of percent. Your existing roof pitch is very likely fine.
- "Tilt equals latitude" is wrong — the true optimum is lower, and increasingly so toward the poles — but it is wrong by only a percent or two.
- An east- or west-facing roof is where the real loss is, and it is worth knowing the number before you commit.