diff --git a/Helios/Source/SolarPanel.cs b/Helios/Source/SolarPanel.cs
index ab72a117d1ac4ccc082c946f7f533405402467d5..e2a09a3e0de9ef948c21a8e72eda5e15fe0ad78d 100644
--- a/Helios/Source/SolarPanel.cs
+++ b/Helios/Source/SolarPanel.cs
@@ -31,7 +31,7 @@ namespace Helios.Source
             return installationCost;
         }
 
-        public double GetPowerOutput(int roofArea, int roofElevation)
+        public double GetPowerOutput(double roofArea, int roofElevation)
         {
             double powerOutput;