diff --git a/message_ix_models/tools/costs/config.py b/message_ix_models/tools/costs/config.py
index 548941b326..d4023469a3 100644
--- a/message_ix_models/tools/costs/config.py
+++ b/message_ix_models/tools/costs/config.py
@@ -53,7 +53,7 @@ class Config:
     method: Literal["constant", "convergence", "gdp"] = "gdp"
 
     #: Model variant for which to project costs.
-    module: Literal["energy", "materials"] = "energy"
+    module: Literal["energy", "materials", "cooling"] = "energy"
 
     #: Use vintages.
     #: