diff --git a/core/metrics/db_profile.go b/core/metrics/db_profile.go
index 0130986db..78d9570ec 100644
--- a/core/metrics/db_profile.go
+++ b/core/metrics/db_profile.go
@@ -18,7 +18,8 @@ func importProfile(entity entity, from time.Time) (*[96]float64, error) {
 		return nil, err
 	}
 
-	rows, err := db.Query(`SELECT min(ts) AS ts, avg(energy) AS energy
+	// COALESCE guards against legacy rows with NULL energy
+	rows, err := db.Query(`SELECT min(ts) AS ts, COALESCE(avg(energy), 0) AS energy
 		FROM meters
 		WHERE meter = ? AND ts >= ?
 		GROUP BY strftime("%H:%M", ts, 'unixepoch', 'localtime')