It seems that solid wood floorboards have a greater impact on warmth than I had previously thought.

I think this because I recently heard the following story from a homeowner:
It's very complicated, but a few years ago I was designing a new house for a friend.
We just recently finished renovating the parents' house.
I was only in charge of planning for my friend's house.
I bought some land, and by chance, a construction company I know was doing the work for me in Hyogo Prefecture.
Since it was a leading company that makes highly insulated houses, we hit it off and I came up with the plan.
I built a house with a Q value of about 2 and perfect solar radiation from the south side.
The floor is the company's standard, and the surface is a composite flooring with a urethane coating.
I had to use it. But of course the house was very warm and my friend
大変満足していました。
A few years later, I recently designed and completed the renovation of my parents' house.
We had a very limited budget, so we didn't have much money to spend on insulation.
I haven't done it yet, but I imagine the Q value was around 5.
Although it faces south, the opening on the south side is much smaller than my friend's house.
However... A friend of mine who went back to his hometown for the first time since the renovation during the New Year holidays said:
"If the floor is made of solid wood, it's going to be really warm. If you just take the floor off, it feels warmer than my house."
This was quite a shocking statement to me.
I don't think there are many examples where such a comparison can be made, but looking at the numbers, it's definitely
The two homes are incomparable, but the difference in their impressions is just whether the flooring is solid wood or not.
I was surprised at the difference. Of course, solid wood floors have better thermal conductivity.
I knew that it would feel warm because it was low. However, this time the difference was dramatically reduced.
I never thought it would make me feel that way.
If you measure the temperature with a thermometer, the temperature of both floorings will naturally be the same under the same conditions.
So why do we feel the warmth differently? It's because the speed at which heat moves is different.
To give a more extreme example, if hot water has a high thermal conductivity, you obviously cannot put it in 90°C water.
The same logic applies to air with low thermal conductivity, so you can put it in a 90°C sauna.
When we looked into how much the thermal conductivity actually differed, we found that the thermal conductivity of cedar and cypress was
About 0.12. There is little data on urethane coating, but from various sources
A guess would be around 0.2 to 0.3, which is roughly a difference of 2 to 3 times.
The formula for perceived temperature is (average temperature of six surfaces + room temperature)/2, but this formula was originally
It seems to have been invented in the West, where people wear shoes all the time. Professor Sugai of Fukuoka University pointed this out.
However, in Japan, the floor temperature must be overestimated to match the actual temperature.
It seems.
After all, it's hard to imagine using anything other than solid wood for flooring.