This is complete for now. I'll update it little by little as I use it. They could put insulation in the walls and ceilings, and dampers on the doors. They might put in windows.

This is not a how-to video.
The method I'm using is not necessarily the right one. Nowadays, you can find out the right way to do things by searching on Google. If you only want results, that's fine too.
But for me, the most important thing is not whether a method is right or wrong, It's about experiencing firsthand why it works or fails.
All work is done personally and at my own risk. Please enjoy it as entertainment only.

For those who want to give to HIRO, Lamp, Yona, and Gwin
https://www.amazon.jp/hz/wishlist/ls/...
https://www.amazon.jp/hz/wishlist/ls/...