diff --git a/components/mitsubishi_heatpump/climate.py b/components/mitsubishi_heatpump/climate.py
index 7c90ca3..9609eed 100644
--- a/components/mitsubishi_heatpump/climate.py
+++ b/components/mitsubishi_heatpump/climate.py
@@ -12,6 +12,7 @@ from esphome.const import (
     CONF_MODE,
     CONF_FAN_MODE,
     CONF_SWING_MODE,
+    PLATFORM_ESP8266
 )
 from esphome.core import CORE, coroutine
 
@@ -97,7 +98,7 @@ CONFIG_SCHEMA = climate.CLIMATE_SCHEMA.extend(
 
 @coroutine
 def to_code(config):
-    serial = HARDWARE_UART_TO_SERIAL[config[CONF_HARDWARE_UART]]
+    serial = HARDWARE_UART_TO_SERIAL[PLATFORM_ESP8266][config[CONF_HARDWARE_UART]]
     var = cg.new_Pvariable(config[CONF_ID], cg.RawExpression(f"&{serial}"))
 
     if CONF_BAUD_RATE in config: