howmuchsun

Solar panel angle in Mixco

In Mixco, fixed panels collect the most energy over a year tilted 14° from horizontal and facing south. But anything between 5° and 25° is within 2% of the best, so the pitch you already have is probably fine.

What is your roof worth?

Of the maximum 97% facing south, 30° pitch
Best here 14° facing south
Good-enough range 5–25° within 2% of the maximum

Every roof, scored

Percentage of the maximum possible annual yield, for each combination of orientation and pitch in Mixco.

Percentage of maximum annual yield by roof orientation (rows) and pitch (columns).
Roof faces 15° 30° 45° 60° 90°
South 98% 100% 97% 88% 75% 43%
South-east / south-west 98% 99% 95% 88% 77% 51%
East / west 98% 95% 90% 82% 73% 52%
North-east / north-west 98% 91% 81% 69% 56% 36%
North 98% 89% 77% 60% 44% 22%

Where "tilt equals your latitude" happens to work

The rule of thumb says tilt your panels at your latitude — 15° for Mixco. The real optimum is 14°, so here the rule happens to be about right.

The rule breaks down further from the equator, where the optimum falls increasingly below the latitude — by around 10 degrees at 50°, and 15 by 65°. Close to the equator the two happen to coincide, so here the rule of thumb is genuinely fine.

Seasonal angles

If you can adjust your panels twice a year, these are the angles to use. Most people should not bother — the gain is small and the ladder is real.

SettingTiltFacing
Fixed, all year14°south
Summersouth
Winter41°south
Flat on the ground

A flat installation here keeps 98% of the maximum; mounted vertically on a wall, 43%.

Other cities in Guatemala

Assumptions

  • These are angles and percentages, never kilowatt-hours. Optimal angles are driven by geometry and are robust. Absolute energy output depends on measured irradiance, cloud, soiling and hardware, none of which are modelled here.
  • Clear sky, no shading. Trees, chimneys, neighbouring buildings and terrain are ignored, and they can dominate everything on this page.
  • Fixed panels. Trackers follow the sun and change the answer entirely.
  • Ordinary ground. Reflectance is taken as 0.2, typical for grass and soil. Snow reflects far more and favours steeper tilts.

Full methodology, sources and known limitations