Generally, the suitable temperature for the fire is below 0℃. This is because the temperature is low, the human body is easy to catch cold and needs to keep warm.

So we can try not to keep warm, and at the same time, it will produce some substances that pollute the air, which is not environmentally friendly. And it is dangerous, so it is not recommended to keep warm. Now we should pay attention to environmental protection and low carbon, and don't do anything that pollutes the air.