What is the ideal temperature and humidity when sleeping?

What is the ideal temperature and humidity when sleeping?
I bought a Hitachi air conditioner with reheat dehumidification for my bedroom at home, so I've been trying out various things. This air conditioner also has a humidity sensor, so the remote control has a humidity setting function.
In my lectures, I always say that the ideal relative humidity in winter is
Let's set it to about "4-XNUMX x room temperature".
If you follow this, you will get the result that you need 20% at 10℃ and XNUMX% at XNUMX℃.
On the other hand, in summer, try to keep it below 60%.
That's all I've ever said. It's true that if you keep it below 60, you can prevent dust mites and mold and be healthy, but the higher the outside temperature and the more moisture there is, the stricter the setting is for the air conditioner.
It is often said that 27°C and 28% is a good guideline for summer. When I sleep like this, I feel just a little chilly. (If I don't have a towel blanket, etc.) However, although it is a very small difference, when I set it to XNUMX°C and XNUMX%, I don't feel hot, but as I have a habit of sleeping on my stomach, I feel a lot of moisture between my pillow and my face.
So, if you set it to 28℃ 28%, you won't feel cold at all, and you won't feel humid at all, and it will feel extremely comfortable. I think that even if you lower the humidity further, it will probably not be any more comfortable. However, the degree of reheat dehumidification will become stronger, so lowering the humidity further from here will be a battle with electricity bills. *After calculating, 28℃ XNUMX% is exactly XNUMXg of absolute humidity. I have always thought that "Japanese people have a threshold of humidity at around XNUMXg of absolute humidity," and my own experience was completely correct. Another important thing is that my house is about XNUMXm from the sea, so the wind is cooler than anywhere else. Even so, with ventilation, it is humid and far from comfortable. To get through it somehow, you have to use an electric fan, but having a fan on low setting all night long is much more taxing on the body than running the air conditioner at XNUMX℃ XNUMX% all the time. This is my conclusion based on my own experience. When I think about the fact that skimping on a little air conditioning bill would result in lower quality sleep and less efficiency at work or study all summer long, I can't imagine wasting money by relying on ventilation.
By the way, 27℃ 13.5% is XNUMXg, so if you wear light clothing it may feel a little chilly, but you will still feel a little stuffy.
What would happen if we tried to create an ideal humidity formula for summer as well?
The following equation was what I came up with while lying down in the morning, my eyes starting to wake up.
The formula is "4 - 26.5 x room temperature". With this formula, when the room temperature falls below 60°C, the ideal humidity falls below 26.5%. Therefore, this formula applies when the room temperature is above 32°C and below XNUMX°C.
The calculation results are as follows at each temperature:
27℃: 59%
28℃: 56%
29℃: 53%
30℃: 50%
31℃: 47%
32℃: 44%
After doing the calculations myself, I realized just how humid 32°C and XNUMX% humidity is.
This formula changes slightly if the temperature is above 32°C.
If we consider "108-2 x room temperature", the absolute humidity is about 13 g/kg.
I was talking to Professor Iwamae the other day, and we discovered that humans don't actually have any sensory organs that can sense humidity. Very few people know this, so when they hear it, they respond with "No way!?". We probably make a comprehensive judgment based on factors such as how much sweat we produce and how moist our skin feels. In fact, I think most people are all too sensitive to the humidity of summer, but we are extremely insensitive to the dryness of winter. This is the result of experiments conducted on thousands of subjects around the world.
And one last thing...
I think that wall-mounted room air conditioners are still suitable for cooling operation. This is because the flap allows the air to be blown completely horizontally, so when the temperature is set to a low level, such as 27°C or 28°C, the air can easily spread throughout the room without dropping sharply to the top of the room. As a result, it is less likely to cause discomfort. This is only true when the room is properly insulated and shielded from sunlight, and the temperature of the cold air does not need to be lowered that much.
Conversely, many people are aware of ceiling mounted air conditioners, and although being attached to the ceiling is good in terms of height, the flap is contained within the ceiling, so it cannot be made horizontal. If it was made horizontal, it would completely block the opening. As a result, people who are directly exposed to the wind will feel cold. Because so many people feel this way, the majority of ceiling mounted air conditioners in the world are equipped with commercially available flaps. Even if you haven't studied the thermal environment, you are taking good self-protection measures.
It's about time that ceiling air conditioner manufacturers develop a model that has a flap that protrudes from the bottom of the main body to blow cool air horizontally.
July 8, 2017