diff --git a/control/json/fan.hpp b/control/json/fan.hpp
index 2a10846..116e50f 100644
--- a/control/json/fan.hpp
+++ b/control/json/fan.hpp
@@ -42,6 +42,8 @@
  */
 class Fan : public ConfigBase
 {
+    friend class Zone;
+
   public:
     /* JSON file name for fans */
     static constexpr auto confFileName = "fans.json";