How to fight cold ?

This summer we tried to save on electricity bill with our "eco-fan". Finally we haven't used air-con even once and reduced our bill of 30% on July-August compare to last year ! Nice shot.
Now we decided to fight with winter too !

The most disappointing thing in isolation of Japanese house is single layered window. These are huge surfaces from where heat can flew away immediately. Of course I can't ask for replacement of windows in my rental house, but we found another solution : shouji !
Shouji are sheets of thick paper on a wooden frame set up on the window. Even if it's very simple it improves greatly isolation ! Cheap, nature-friendly, traditional, ... it's perfect. You can buy shouji in specialized shop of course, but frame of windows is often irregular so it's hard to find the ones that fit perfectly your place. Order a custom-built one is too expensive. Then let's make it ourself ! For one window, it costed 2,300 yen of wood, paper, glue and metal fastening. We could make it in one hour and are very proud of the result, there is almost no space left between the wall and the frame of the shouji. Of course it's also a great pleasure to make something by our own. Now we are waiting to see how much it will change temperature in our house...
We've also found another interest in shouji. One of the bad point of using them is that room gets darker because the paper stops a little of light from outside. But in winter, this inconvenience becomes rather a advantage. Due to winter season, when we're at home it's still/yet night outside so we have no chance to enjoy sunlight at home anyway. On the contrary, if we turn on light inside the room, it reflects on white paper and the room gets much clearer compare with the window alone. That was a good surprise. By the way, I was very pleased by the name of the pattern of our paper. It's called 'unryu', it means 'dragons cloud'. Nice isn't it ?

Now I had another idea to fight cold. As a computer geek I know well how much computer can generate heat. Put your hand in front of the fan of your laptop and you'll be surprised if you haven't noticed yet. I was wondering how to re-use this heat instead of loosing it. The point is, it's very weak, no way to heat a whole room with one laptop. So I thought how could I concentrate and keep the generated heat where I need it : near me. Here again traditional furniture of japan gave me the solution ! I invented the 'kopyutatsu', which is a play on words 'konpyuta' (computer in japanese) and 'kotatsu'. Kotatsu is a japanese low table with a heating system inside and a kind of futon/skirt around it. The skirt avoid heat to escape from under the table and everybody enjoy putting his legs under the table. Some people eventually end up sleeping under it ! As I'm using my laptop as a central unit (with external screen, keyboard, ...), I don't need to have access to it. Then I put it under my low desk, and I've closed all four sides of the desk with thick fabric. It works like a charm, no more frozen feet ! The greatest pleasure is thinking of it like recycling energy. The weak point is it takes little time to heat up, and you need to use some heavy software to get your computer hot. So it's a good solution only for those who use a lot their computer. If you use it only one hour to look at your email you won't notice any change...

And you what are your tricks to fight cold ?