Why your feet feel colder because they have fewer cold spots

Why your feet feel colder because they have fewer cold spots
First, we would like to announce an emergency tour.
My younger brother and his wife renovated their apartment while keeping costs to a minimum.
Complete replacement of water facilities, reinforcement of insulation, consideration of soundproofing, and as barrier-free as possible.
This renovation focused solely on the use of natural materials.
For those who want to renovate their apartment using natural materials
I recommend going to Master Plan.
http://reno.mpl.co.jp/
Instead, we want to keep costs down while still maintaining basic performance.
If you are looking to live in your home for a long time, please come and see it.
Reservations are required, so if you would like to attend, please make a reservation using the form below.
http://organic-studiohyogo.jp/blog/?p=3036
In that case, please let us know by saying, "I saw the Matsuo Design Office blog."
Here is a continuation from yesterday. Why do our feet, which have fewer cold spots, feel colder?
To put it simply, in most typical homes, the air temperature at and near the floor is
That's because it's low.
For example, if the room temperature is set to 20°C using an air conditioner in a home with next-generation energy-saving standards,
Even though the temperature at head height is 20°C, the floor temperature is usually around 17°C.
If the room temperature felt by the cold spot at the head is 20°C and the average radiant temperature is 18°C,
The PMV I mentioned the other day is -1.12. (About XNUMX% of people feel cold.)
If all other conditions are the same and the room temperature felt by the cold spot at the feet is 17°C and the average radiant temperature is also 17°C,
It will worsen to -1.676 (about XNUMX% of people will feel cold).
Normally, PMV is used as an index of heat felt by a single person, but this time, to make it easier to understand, we deliberately used it for each cold spot.
I tried comparing them.
There are a huge number of cold spots in each person. How cold is each cold spot relative to the brain?
The majority of the information is "warm," and only a small part of the feet is "cold."
Let's say that the following information is provided.
In PMV, these are averaged as a whole, but it seems that humans feel pleasure and discomfort based on the average.
It doesn't seem to be the case. If there is even one uncomfortable spot, the discomfort there will be intense and make the brain feel "cold."
I think so.
This is true even in the summer. I once tried to circulate the cold air from an underfloor air conditioner under the floor.
(Please don't do this) It's true that the floor will get cold, but it won't be comfortable at all.
In summer, hot air rises, so your head will generally be hotter than your feet.
If we think of PMV for each temperature point, even if the feet are cool, the head may feel hot.
This information is transmitted to the brain. As a result, even if the average temperature is cool, it still feels "hot."
That's what I feel.
From this, we can see that it is very important that the floor does not get cold in winter.
According to ISO (International Organization for Standardization) standards, the ideal temperature difference between the top and bottom should be within 3°C.
This value is easily cleared in a high-performance house.
Even if the temperature is 20℃, if the floor temperature is 17℃, it will be difficult to feel warm.
That's why we use air conditioners to send warm air under the floor to keep the floor temperature "not too cold."
In the case of general floor heating, the surface temperature can exceed 30°C.
According to the ISO, the ideal floor temperature is between 19°C and 26°C, which is the most satisfactory.
The highest temperature is around 24℃. Also, if the floor is 30℃ and the room temperature is 18℃, the temperature difference between the top and bottom will be
The temperature can reach 12°C, which is quite uncomfortable.
This is just my opinion, but the cold spot at your feet is saying "it's hot" while the cold spot on your head is saying "it's cold"
Humans have a thermoregulatory function called the autonomic nervous system, but
I think that in this state, the autonomic nervous system itself becomes confused, making it difficult to properly regulate body temperature.
Similarly, from the perspective of summer, it is important to keep out radiant heat from above as much as possible, especially on the second floor and in the eaves.
From the perspective of blocking out heat, you can see that good insulation of the roof and ceiling is extremely important.
The "strength development method" is said to be good for children's education and organizational development, but
When it comes to the indoor environment, it is important to "improve shortcomings."
⇒As always, I will conclude by saying that the most important thing is to insulate your windows.