diff --git a/homeassistant/components/modbus/climate.py b/homeassistant/components/modbus/climate.py
index 75a1f846c76..36871c68d9b 100644
--- a/homeassistant/components/modbus/climate.py
+++ b/homeassistant/components/modbus/climate.py
@@ -33,7 +33,12 @@ from .const import (
     CONF_MIN_TEMP,
     CONF_STEP,
     CONF_TARGET_TEMP,
-    DEFAULT_STRUCT_FORMAT,
+    DATA_TYPE_INT16,
+    DATA_TYPE_INT32,
+    DATA_TYPE_INT64,
+    DATA_TYPE_UINT16,
+    DATA_TYPE_UINT32,
+    DATA_TYPE_UINT64,
     MODBUS_DOMAIN,
 )
 from .modbus import ModbusHub
@@ -145,16 +150,28 @@ class ModbusThermostat(BaseStructPlatform, RestoreEntity, ClimateEntity):
         """Set new target temperature."""
         if ATTR_TEMPERATURE not in kwargs:
             return
-        target_temperature = int(
-            (kwargs.get(ATTR_TEMPERATURE) - self._offset) / self._scale
-        )
-        byte_string = struct.pack(self._structure, target_temperature)
-        struct_string = f">{DEFAULT_STRUCT_FORMAT[self._data_type]}"
-        register_value = struct.unpack(struct_string, byte_string)[0]
+        target_temperature = (
+            float(kwargs.get(ATTR_TEMPERATURE)) - self._offset
+        ) / self._scale
+        if self._data_type in [
+            DATA_TYPE_INT16,
+            DATA_TYPE_INT32,
+            DATA_TYPE_INT64,
+            DATA_TYPE_UINT16,
+            DATA_TYPE_UINT32,
+            DATA_TYPE_UINT64,
+        ]:
+            target_temperature = int(target_temperature)
+        as_bytes = struct.pack(self._structure, target_temperature)
+        raw_regs = [
+            int.from_bytes(as_bytes[i : i + 2], "big")
+            for i in range(0, len(as_bytes), 2)
+        ]
+        registers = self._swap_registers(raw_regs)
         result = await self._hub.async_pymodbus_call(
             self._slave,
             self._target_temperature_register,
-            register_value,
+            registers,
             CALL_TYPE_WRITE_REGISTERS,
         )
         self._available = result is not None
diff --git a/tests/components/modbus/test_climate.py b/tests/components/modbus/test_climate.py
index b58822644be..b872f4fe302 100644
--- a/tests/components/modbus/test_climate.py
+++ b/tests/components/modbus/test_climate.py
@@ -3,7 +3,15 @@ import pytest
 
 from homeassistant.components.climate import DOMAIN as CLIMATE_DOMAIN
 from homeassistant.components.climate.const import HVAC_MODE_AUTO
-from homeassistant.components.modbus.const import CONF_CLIMATES, CONF_TARGET_TEMP
+from homeassistant.components.modbus.const import (
+    CONF_CLIMATES,
+    CONF_DATA_TYPE,
+    CONF_TARGET_TEMP,
+    DATA_TYPE_FLOAT32,
+    DATA_TYPE_FLOAT64,
+    DATA_TYPE_INT16,
+    DATA_TYPE_INT32,
+)
 from homeassistant.const import (
     ATTR_TEMPERATURE,
     CONF_ADDRESS,
@@ -110,6 +118,46 @@ async def test_service_climate_update(hass, mock_pymodbus):
     assert hass.states.get(ENTITY_ID).state == "auto"
 
 
+@pytest.mark.parametrize(
+    "data_type, temperature, result",
+    [
+        (DATA_TYPE_INT16, 35, [0x00]),
+        (DATA_TYPE_INT32, 36, [0x00, 0x00]),
+        (DATA_TYPE_FLOAT32, 37.5, [0x00, 0x00]),
+        (DATA_TYPE_FLOAT64, "39", [0x00, 0x00, 0x00, 0x00]),
+    ],
+)
+async def test_service_climate_set_temperature(
+    hass, data_type, temperature, result, mock_pymodbus
+):
+    """Run test for service homeassistant.update_entity."""
+    config = {
+        CONF_CLIMATES: [
+            {
+                CONF_NAME: CLIMATE_NAME,
+                CONF_TARGET_TEMP: 117,
+                CONF_ADDRESS: 117,
+                CONF_SLAVE: 10,
+                CONF_DATA_TYPE: data_type,
+            }
+        ]
+    }
+    mock_pymodbus.read_holding_registers.return_value = ReadResult(result)
+    await prepare_service_update(
+        hass,
+        config,
+    )
+    await hass.services.async_call(
+        CLIMATE_DOMAIN,
+        "set_temperature",
+        {
+            "entity_id": ENTITY_ID,
+            ATTR_TEMPERATURE: temperature,
+        },
+        blocking=True,
+    )
+
+
 test_value = State(ENTITY_ID, 35)
 test_value.attributes = {ATTR_TEMPERATURE: 37}