diff --git a/var/spack/repos/builtin/packages/dd4hep/package.py b/var/spack/repos/builtin/packages/dd4hep/package.py
index 112536afab61080ab7f5e27364304c8427c6a9a6..6f1b2e8a8bfb467e838e2a5cef4f39aff7d15211 100644
--- a/var/spack/repos/builtin/packages/dd4hep/package.py
+++ b/var/spack/repos/builtin/packages/dd4hep/package.py
@@ -72,6 +72,8 @@ def cmake_args(self):
     def setup_run_environment(self, env):
         # used p.ex. in ddsim to find DDDetectors dir
         env.set("DD4hepINSTALL", self.prefix)
+        env.set("DD4hep_DIR", self.prefix)
+        env.set("DD4hep_ROOT", self.prefix)
 
     def url_for_version(self, version):
         # dd4hep releases are dashes and padded with a leading zero