0.38.1 - A lot errors with climate component

After upgrade from 0.37.1 to 0.38.1 I have in log a lot of errors with climate component

17-02-12 16:12:53 ERROR (MainThread) [homeassistant.core] Error doing job: Task exception was never retrieved
Traceback (most recent call last):
  File "/usr/lib/python3.4/asyncio/tasks.py", line 237, in _step
    result = next(coro)
  File "/srv/homeassistant/homeassistant_venv/lib/python3.4/site-packages/homeassistant/helpers/entity.py", line 220, in async_update_ha_state
    attr = self.state_attributes or {}
  File "/srv/homeassistant/homeassistant_venv/lib/python3.4/site-packages/homeassistant/components/climate/__init__.py", line 417, in state_attributes
    ATTR_MIN_TEMP: self._convert_for_display(self.min_temp),
  File "/srv/homeassistant/homeassistant_venv/lib/python3.4/site-packages/homeassistant/components/climate/__init__.py", line 676, in min_temp
    return convert_temperature(7, TEMP_CELSIUS, self.temperature_unit)
  File "/srv/homeassistant/homeassistant_venv/lib/python3.4/site-packages/homeassistant/util/temperature.py", line 27, in convert
    TEMPERATURE))
ValueError: None is not a recognized temperature unit.

I use Danfoss 014G0013 Z-Wave thermostats. Any solution for that?