diff --git a/templates/definition/tariff/open-meteo.yaml b/templates/definition/tariff/open-meteo.yaml
index 1f2973d6a..bf5ca8adc 100644
--- a/templates/definition/tariff/open-meteo.yaml
+++ b/templates/definition/tariff/open-meteo.yaml
@@ -111,7 +111,7 @@ render: |
                         ( ($h.temperature_2m[$i]
                             + ($h.temperature_2m[$i-1] // $h.temperature_2m[$i])
                           ) / 2)
-                        + ($h.global_tilted_irradiance[$i] / 800.0) * rossmodel - 25.0
+                        + $h.global_tilted_irradiance[$i] * rossmodel - 25.0
                       )
                     ))
                 * (1 - calculate_damping($time;