diff --git a/env.cpp b/env.cpp
index ab4b35c..09dd985 100644
--- a/env.cpp
+++ b/env.cpp
@@ -20,6 +20,8 @@
 #include "env.hpp"
 #include "hwmon.hpp"
 
+namespace env {
+
 std::string getEnv(
     const char* prefix, const SensorSet::key_type& sensor)
 {
@@ -76,4 +78,6 @@
     return content;
 }
 
+}  // namespace env
+
 // vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4