Generally speaking, the most comfortable indoor temperature for human body is 15- 18℃. If the indoor air is not circulating or the relative humidity is less than 35%, and the indoor temperature exceeds 25℃, the human body will begin to absorb the external heat, and you will feel hot. If the temperature exceeds 35℃, the sweat glands of the human body will start at this time, accumulate body temperature through slight sweating, accelerate the heartbeat and accelerate the blood circulation. You will feel dizzy, unwell, tired, sleepy and extremely hot. Conversely, when the temperature is below 4℃, you will feel cold. When the room temperature is 8- 18℃, the human body will radiate heat to the outside, and the indoor relative humidity is between 40% and 60%, so you will feel comfortable and healthy. In the comfortable indoor temperature range, the influence of humidity on human body is not obvious. But when the temperature is 28℃ and the relative humidity reaches 90%, you will feel the temperature reaches 34℃. This is because when the humidity is high, the water vapor content in the air is high and the evaporation capacity is low, so it is difficult to evaporate a large amount of sweat discharged by the human body and the heat in the body cannot be dissipated smoothly. So, you will feel stuffy. Only in terms of relative humidity, the most suitable air relative humidity is 40%-50%, because in this humidity range, the life span of bacteria in the air is the shortest, and human skin will feel comfortable and breathe evenly and normally. According to meteorologists, when the relative humidity reaches 30%, the temperature of heatstroke is 38℃. When the relative humidity reaches 80% and the temperature is 365438 0℃, people with weak constitution sometimes suffer from heatstroke. If you encounter low temperature and high humidity in winter, people will feel wet and cold.

Healthy humidity environment is 45% ~ 65%. Under such humidity conditions, the human body feels most comfortable, and various germs are not easy to spread. Humidity higher than 65% will cause discomfort to human respiratory system and mucosa and reduce immunity.