diff --git a/homeassistant/components/generic_thermostat/climate.py b/homeassistant/components/generic_thermostat/climate.py
index 13e23b962c9..b765dbbfda4 100644
--- a/homeassistant/components/generic_thermostat/climate.py
+++ b/homeassistant/components/generic_thermostat/climate.py
@@ -412,8 +412,8 @@ class GenericThermostat(ClimateDevice, RestoreEntity):
                     if not long_enough:
                         return
 
-            too_cold = self._target_temp - self._cur_temp >= self._cold_tolerance
-            too_hot = self._cur_temp - self._target_temp >= self._hot_tolerance
+            too_cold = self._target_temp >= self._cur_temp + self._cold_tolerance
+            too_hot = self._cur_temp >= self._target_temp + self._hot_tolerance
             if self._is_device_active:
                 if (self.ac_mode and too_cold) or (not self.ac_mode and too_hot):
                     _LOGGER.info("Turning off heater %s", self.heater_entity_id)