Baby room temperature

Ti

Sooo I’ve been trying to get the baby’s room temperature right and it’s so hard... I live in china and there’s isn’t central heating meaning no ac or thermostat. We have a heater in her bedroom but sometimes I turn it on and leave the window open. Next time I come in it’s too hot so I leave the heater off and shut the window then it’s too cold. I don’t know 🤷‍♀️ what to do.