Balcony railing vs tilted panels: how much do you lose?
Hanging panels flat on a balcony railing is often the only option in an apartment. It works, but you get less power than from panels tilted toward the sun.
The short answer
A vertical panel facing south makes 43% to 79% of what the same panel tilted at 20° makes, depending on the state. The smallest loss is in Alaska (79%) and the largest in Hawaii (43%). In the 10 states with a plug-in law, the range is 61–77%.
Why tilt matters
A panel makes the most power when sunlight hits it head-on. For much of the year, and above all in summer, the midday sun is high in the sky. It strikes a vertical panel at a steep, glancing angle, so less light lands on each square foot. A panel tilted back toward the sky catches that high sun far better.
Vertical panels do relatively well where and when the sun stays low: farther north, and in winter. Where the sun climbs high for much of the year, they lose more. In our data, Alaska loses the least and Hawaii the most.
Direction matters too. These figures assume panels face due south with no shade. East- or west-facing balconies, and shade from buildings or the balcony above, cut output further.
Yearly solar output for tilted and vertical panels, by state
Solar output: NREL (National Laboratory of the Rockies) PVWatts v8, typical meteorological year weather, run for each state capital with 14% system losses, ideal tilt (20°, facing south) and vertical railing (90°, facing south) (PVWatts documentation).
The 800 W kit figures are panel watts ÷ 1,000 × output per kW, before any inverter limit.
One location per state (the capital). Output varies within a state, especially in large states.
Solar data last checked November 10, 2026.
This page is general information, not legal or electrical advice. Laws change and utilities differ. Check the linked official sources, your lease or HOA rules, and your utility before you buy or install anything. Full disclaimer.