White smoke on the chimney
Because garbage contains fluid and combustion process produces water, the waste gas exhausted from the chimney contains massive water vapor. When the temperature drops in winter or the relative humidity suddenly rises up, the water vapor would reach the dew point and condense into white smoke. When the atmospheric temperature rises and the relative humidity decreases, the white smoke would disappear. That is a natural phenomenon similar to the white smoke coming out from our mouths when we breath during the winter and not happen during the summer. The white smoke is caused by water vapor and is harmless to human. Please don't worry about it.
For any other questions, please contact us through service mailbox or by phone.