diff --git a/esphome/components/bang_bang/bang_bang_climate.cpp b/esphome/components/bang_bang/bang_bang_climate.cpp
index c043f6b7de..4b41684707 100644
--- a/esphome/components/bang_bang/bang_bang_climate.cpp
+++ b/esphome/components/bang_bang/bang_bang_climate.cpp
@@ -21,7 +21,12 @@ void BangBangClimate::setup() {
     restore->to_call(this).perform();
   } else {
     // restore from defaults, change_away handles those for us
-    this->mode = climate::CLIMATE_MODE_HEAT_COOL;
+    if (supports_cool_ && supports_heat_)
+      this->mode = climate::CLIMATE_MODE_HEAT_COOL;
+    else if (supports_cool_)
+      this->mode = climate::CLIMATE_MODE_COOL;
+    else if (supports_heat_)
+      this->mode = climate::CLIMATE_MODE_HEAT;
     this->change_away_(false);
   }
 }
@@ -43,12 +48,13 @@ climate::ClimateTraits BangBangClimate::traits() {
   traits.set_supports_current_temperature(true);
   traits.set_supported_modes({
       climate::CLIMATE_MODE_OFF,
-      climate::CLIMATE_MODE_HEAT_COOL,
   });
   if (supports_cool_)
     traits.add_supported_mode(climate::CLIMATE_MODE_COOL);
   if (supports_heat_)
     traits.add_supported_mode(climate::CLIMATE_MODE_HEAT);
+  if (supports_cool_ && supports_heat_)
+    traits.add_supported_mode(climate::CLIMATE_MODE_HEAT_COOL);
   traits.set_supports_two_point_target_temperature(true);
   if (supports_away_)
     traits.set_supported_presets({
@@ -59,12 +65,8 @@ climate::ClimateTraits BangBangClimate::traits() {
   return traits;
 }
 void BangBangClimate::compute_state_() {
-  if (this->mode != climate::CLIMATE_MODE_HEAT_COOL) {
-    // in non-auto mode, switch directly to appropriate action
-    //  - HEAT mode -> HEATING action
-    //  - COOL mode -> COOLING action
-    //  - OFF mode -> OFF action (not IDLE!)
-    this->switch_to_action_(static_cast<climate::ClimateAction>(this->mode));
+  if (this->mode == climate::CLIMATE_MODE_OFF) {
+    this->switch_to_action_(climate::CLIMATE_ACTION_OFF);
     return;
   }
   if (isnan(this->current_temperature) || isnan(this->target_temperature_low) || isnan(this->target_temperature_high)) {