diff --git a/cal_and_val/thermal/cal_hev.py b/cal_and_val/thermal/cal_hev.py
index 46951959..03804f7b 100644
--- a/cal_and_val/thermal/cal_hev.py
+++ b/cal_and_val/thermal/cal_hev.py
@@ -391,6 +391,7 @@ def get_exp_pwr_hvac(df):
         # - HVAC PID controls for cabin (not for battery because Sonata has
         #   passive thermal management, but make sure to do battery thermal
         #   controls for BEV)
+        # - HVAC cop frac
         # - engine temperature-dependent efficiency parameters
         # - engine thermal
         #     - thermal mass