COMPOUND / FREE SOLAR DESIGN TOOL
Which way should your solar panels face?
Turn the roof through a full 360°. See how direction, tilt and system size change estimated solar generation in Ireland. No sign-up required.
A south-facing roof isn't your only option. Explore any angle, then refine your numbers using the European Commission's PVGIS model before requesting installation quotes.
Tap, drag or use the slider to turn your panels.
ESTIMATED ANNUAL ELECTRICITY GENERATION
Based on the settings and orientation shown.
Enter a system size above 0 and no more than 30 kWp, a roof pitch from 0° to 90°, and shading of 0–50%.
Choose the nearest representative town, not your exact roof. The shading field is a simple illustrative annual deduction, not a shade survey.
THE SEASONS MATTER
Generation across the year.
Monthly output changes with daylight, seasonal sun angle, panel direction and your selected roof pitch.
Tap a bar, or use the chart’s left and right arrow keys, to see the exact monthly kWh. Turn the compass above to compare roof directions.
The instant dial uses a simplified sun-path and diffuse-light model calibrated to broad indicative Irish annual yields. It is not a site-specific forecast. Choose Open PVGIS calculator to check the estimate using the European Commission's official PVGIS website ↗. PVGIS opens separately: enter your exact location, roof pitch, system size and orientation, checking its azimuth convention. Compound does not send your settings to PVGIS. The simplified model on this page does not measure trees, chimneys, roof obstructions or future weather.
Now, does it pay back?
Take the estimated kWh per kWp into our solar payback calculator, then compare installer quotes on the same generation assumptions. Confirm final yield predictions with your installer.
How solar panel direction works
The compass uses degrees clockwise from north: 0° is north, 90° east, 180° south and 270° west. PVGIS uses a different angle convention internally; Compound converts your compass bearing automatically. For two roof faces, calculate each separately with its own kWp and add the generation estimates. An east-west layout can spread electricity production across the morning and afternoon even where total annual yield is below due south. Read our east-versus-west Irish solar guide for a deeper explanation.