diff --git a/mainloop.cpp b/mainloop.cpp
index c1b3fe3..5f2b33d 100644
--- a/mainloop.cpp
+++ b/mainloop.cpp
@@ -58,7 +58,24 @@
 
     for (auto& i : *sensors)
     {
-        auto value = std::make_tuple(std::move(i.second));
+        // Ignore inputs without a label.
+        std::string envKey = "LABEL_" + i.first.first + i.first.second;
+        std::string label;
+
+        auto env = getenv(envKey.c_str());
+
+        if (env)
+        {
+            label.assign(env);
+        }
+
+        if (label.empty())
+        {
+            continue;
+        }
+
+        auto value = std::make_tuple(std::move(i.second), std::move(label));
+
         state[std::move(i.first)] = std::move(value);
     }