diff --git a/CHANGELOG.md b/CHANGELOG.md
index 246ba4486..c339e9e7b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -26,6 +26,11 @@ Classify the change according to the following categories:
     ##### Removed
     ### Patches
 
+## v3.16.1
+### Patches
+##### Changed
+- `load_builder`: EnSite grid efficiency `grid.eff` was changed from 99% --> 100%
+
 ## v3.16.0
 ### Minor Updates
 #### Added
diff --git a/load_builder/views.py b/load_builder/views.py
index 562d66349..5aa65fac7 100644
--- a/load_builder/views.py
+++ b/load_builder/views.py
@@ -195,7 +195,7 @@ def _num(name, cast=float, positive=False, allow_zero=True):
             'type': 'Grid',
             'pMax': int(ems_cfg.get('pChgCap', 0)),  # no fallback; zero if not derived/overridden
             'pMin': 0,
-            'eff': 0.99,
+            'eff': 1.0,
         }
     }
     for cat, charger_cfg in chargers.items():