diff --git a/homeassistant/components/heatmiser/climate.py b/homeassistant/components/heatmiser/climate.py
index 24a0c88b45a..566a4696a73 100644
--- a/homeassistant/components/heatmiser/climate.py
+++ b/homeassistant/components/heatmiser/climate.py
@@ -76,7 +76,12 @@ class HeatmiserV3Thermostat(ClimateEntity):
     """Representation of a HeatmiserV3 thermostat."""
 
     _attr_hvac_modes = [HVACMode.HEAT, HVACMode.OFF]
-    _attr_supported_features = ClimateEntityFeature.TARGET_TEMPERATURE
+    _attr_supported_features = (
+        ClimateEntityFeature.TARGET_TEMPERATURE
+        | ClimateEntityFeature.TURN_OFF
+        | ClimateEntityFeature.TURN_ON
+    )
+    _enable_turn_on_off_backwards_compatibility = False
 
     def __init__(self, therm, device, uh1):
         """Initialize the thermostat."""