diff --git a/esphome/const.py b/esphome/const.py
index 535207958d..a683ec4176 100644
--- a/esphome/const.py
+++ b/esphome/const.py
@@ -629,7 +629,7 @@ UNIT_DEGREES = '°'
 UNIT_EMPTY = ''
 UNIT_G = 'G'
 UNIT_HECTOPASCAL = 'hPa'
-UNIT_HERTZ = 'hz'
+UNIT_HERTZ = 'Hz'
 UNIT_KELVIN = 'K'
 UNIT_KILOMETER = 'km'
 UNIT_KILOMETER_PER_HOUR = 'km/h'