diff --git a/common/time.yaml b/common/time.yaml
index c77a7db..c22732c 100644
--- a/common/time.yaml
+++ b/common/time.yaml
@@ -1,3 +1,6 @@
+substitutions:
+  time_source: homeassistant_time
+
 time:
   - platform: homeassistant
     id: homeassistant_time