diff --git a/src/main/java/gregtech/common/tileentities/machines/multi/GT_MetaTileEntity_Cleanroom.java b/src/main/java/gregtech/common/tileentities/machines/multi/GT_MetaTileEntity_Cleanroom.java
index c5ba53f2..100149a9 100644
--- a/src/main/java/gregtech/common/tileentities/machines/multi/GT_MetaTileEntity_Cleanroom.java
+++ b/src/main/java/gregtech/common/tileentities/machines/multi/GT_MetaTileEntity_Cleanroom.java
@@ -134,7 +134,7 @@ public boolean checkMachine(IGregTechTileEntity aBaseMetaTileEntity, ItemStack a
 	}
 
 	if(doorState){
-		mEfficiency=0;
+		mEfficiency=Math.max(0,mEfficiency-200);
 	}
 
 return true;