diff --git a/config/config.default.yaml b/config/config.default.yaml
index 9e8f57a6..7f1f2034 100644
--- a/config/config.default.yaml
+++ b/config/config.default.yaml
@@ -654,7 +654,7 @@ solving:
     track_iterations: false
     min_iterations: 4
     max_iterations: 6
-    transmission_losses: 0
+    transmission_losses: 2
     linearized_unit_commitment: true
     horizon: 365
 
diff --git a/doc/release_notes.rst b/doc/release_notes.rst
index 03d9318d..09417727 100644
--- a/doc/release_notes.rst
+++ b/doc/release_notes.rst
@@ -10,6 +10,9 @@ Release Notes
 Upcoming Release
 ================
 
+* Default to approximating transmission losses in HVAC lines
+  (``transmission_losses: 2``).
+
 * Remove all negative loads on the ``co2 atmosphere`` bus representing emissions
   for e.g. fixed fossil demands for transport oil. Instead these are handled
   more transparently with a fixed transport oil demand and a link taking care of