Balcony Solar Atlas

Balcony solar calculator

Get a rough estimate of production, savings and simple payback using your state's sunlight and electricity price. Adjust the railing direction and your home's daytime load to compare setups.

Estimates update as you change any field. Copy the result link to save or share your setup.

Which way does your balcony or railing face?
Estimated simple payback
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Yearly savings
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Yearly production
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Share you use yourself
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10-year net savings
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Unused output (no export credit)
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State-level estimate. Local weather, hourly use, installation costs and tariffs can change the result. Model limits.

How to fill it in

  • Facing. Stand on the balcony looking out. A phone compass app tells you the direction. If it is between two options, pick the closer one.
  • Mounting. Most railing kits hang the panels vertically. A tilting bracket or stand makes much more, if your building allows it.
  • Always-on load. What your home draws when nothing is actively being used: fridge, router, standby electronics. Use measured daytime consumption; the model treats this value as constant during every production hour.
  • Inverter limit. The microinverter's maximum AC output, printed on its label. Check your state page for its output cap.

Electricity price. Enter the per-kWh energy charge you avoid, excluding fixed monthly charges. The default state average can overstate savings if your bill contains substantial fixed charges.

Why the share you use matters

Plug-in kits generally earn nothing for power that flows back to the grid, so the calculator only counts the energy your home uses at the moment it is produced.

Share of solar output you use yourself, by household background load Share used increases with constant household load in our Baltimore reference scenario. 0% 25% 50% 75% 100% 0200400600800 Constant household draw (W) 300 W load, 800 W kit: about 80% used

At a 300 W constant load, this 800 W reference kit uses 80% of its generation at home.

Baltimore, Maryland: PVGIS ERA5 typical year, 800 W panels and inverter, vertical south-facing mount, no additional shade. Each point uses the same production model as the calculator, with a constant load and no export credit. Actual hourly consumption varies.

What this estimate does not include

  • Your exact address, local weather or a measured hourly load profile. One representative city and a constant load cannot capture every balcony.
  • Installation, outlet, circuit or mounting work unless you include it in the kit price. Add those costs before comparing payback.
  • Time-of-use rates. If your midday price is lower than average, savings will be lower.
  • Changes in electricity prices. We hold the rate flat for ten years; actual rates may rise or fall.
  • Snow, unusual shading patterns and panel faults.

Data: U.S. EIA, Electric Power Monthly, Table 5.6.B (YTD through August 2026); JRC PVGIS ERA5 typical-year weather; hourly production and self-use modeled with pvlib. Full method.