Tilt your solar panels to 42.1° facing south in TR22. That is the most efficient fixed angle for its latitude of 49.89°. The full breakdown, including seasonal and monthly adjustments, is below.
The TR22 postcode district is centered 39 miles from Penzance, at latitude 49.89°. Every angle here is calculated from that center rather than from the nearest large town. Latitude moves the answer very little in Britain: across the whole country, from the Isles of Scilly to Shetland, the best fixed tilt only runs from 42.1° to 45.9°.
Today, the most efficient tilt for photovoltaic panels in TR22 is 45.3°, facing south. At solar noon the sun sits 44.7° above the horizon. Setting your panels to this angle keeps them as close to perpendicular to the sun as possible, which is where they generate the most electricity.
Your photovoltaic panels need to be angled facing south. TR22 is in the northern hemisphere, so panels catch the most sun facing south.
If you're mounting the photovoltaic panels at a stationary angle, such as on your roof, the most efficient angle is 42.1°.
If you're planning to change the angle of your photovoltaic panels twice per year, the most efficient angle is 25.4° facing south in summer months and 62.9° facing south in winter months.
When changing the angle of your photovoltaic panels each season, the most efficient angle is 21.6° facing south in summer months and 68.4° facing south in winter months, and 46.6° facing south in autumn and spring months.
If you adjust your photovoltaic panels every month, the table below gives the most efficient angle for TR22 throughout the year. The shallowest angle is 26.5° in June, and the steepest is 73.3° in December.
| Month | Optimal tilt | Sun angle at noon |
|---|---|---|
| January | 70.0° | 20.0° |
| February | 61.1° | 28.9° |
| March | 50.3° | 39.7° |
| April | 38.3° | 51.7° |
| May | 29.8° | 60.2° |
| June | 26.5° | 63.5° |
| July | 29.5° | 60.5° |
| August | 38.1° | 51.9° |
| September | 50.1° | 39.9° |
| October | 61.7° | 28.3° |
| November | 70.3° | 19.7° |
| December | 73.3° | 16.7° |
The sun angle at noon is how high the sun sits above the horizon at midday. Facing your panels south at the tilt shown for each month keeps them as close to perpendicular to the sun as possible, which is where they generate the most electricity.
It comes out of your latitude. TR22 sits at 49.89°, which puts the best fixed angle at 42.1°. Near the equator the midday sun is almost overhead, so panels lie close to flat, around 3°. The further from the equator you are, the lower the sun sits, and the steeper your panels have to stand to face it squarely.
The climb is not one for one. At 30° of latitude the best fixed tilt is about 31°, but at 60° of latitude it is about 46°, not 60°. The optimum flattens off toward the poles because the winter sun is low and much of the light arriving is diffuse rather than direct. Every angle on this page comes from a curve fitted to measured optimal-slope data for 52 cities, so it follows that flattening instead of assuming tilt equals latitude. See how the two compare.
The angle is settled. Here is what is worth checking on the panels themselves:
Postcode district data contains OS data © Crown copyright and database right, and Royal Mail data © Royal Mail copyright and database right, used under the Open Government Licence v3.