Thanks @jivesinger . I did try this in one of the iterations but I get the following error when I call the service from developers tab. It validates the Configuration though.
climate.set_temperature
Failed to call service climate/set_temperature. must contain at least one of temperature, target_temp_high, target_temp_low.
Fair point… I broke the service call and just gave the temperature with the template (also removed hvac_mode). Still the service refuses to be called.
Maybe data_template does not work with this service.