Chizakura wrote: ↑Wed Feb 05, 2025 6:29 am
Must be a blessing of the north then. I guess my reply was more targeted on people living in Tokyo in typical apartments there, it does not apply to cases like yours then. I should have clarified that, apoligies.
No problem. I should also add that we live in a two-story house, not a manshon, and there is a fan running 24/7 on each floor.
Chizakura wrote: ↑Wed Feb 05, 2025 6:29 am
Ah no, this is a misunderstanding on your side. You need to look at *absolute* humidity and not relative one. Basically, if the outside air has 74% relative humidity at 0 degrees celcius (14 degrees fahrenheit) and you let it into your home and heat it up to 20 degrees then relative humidity will drop to ~22%. So less than 32%. So you will make the indoor air more dry. (you can calculate it here: https://www.lenntech.com/calculators/hu ... midity.htm)
Gotcha. That probably explains why houses are so dry up here in winter. That and the constant heating.
Chizakura wrote: ↑Wed Feb 05, 2025 6:29 am
Actually, it won't take much energy. Have you ever tried it? Really, heat your home to 20 degrees and keep it like that for a day. Then open everything for just 1 or 2 minutes and close it again. You will see that you'll get to almost 20 degrees indoor room temperature quite quickly even if your AC is not running. If you don't believe it, try it. The reason is that your walls, floor, roof store multiple times the heat than what the whole air in your home can store. To be more specific, one liter of concrete stores 1500 times as much heat energy than one liter of air. 1500! That means to cool down one liter of concrete from 20 degrees to 10 degrees takes 1500 liters of air that is 0 degrees cold.
I can't quite believe that 100% of the air would be replaced in one or two minutes, unless it were blowing a gale outside, but I take your point. Actually our walls are made of wood, not concrete, so not sure how much heat they can retain.
Chizakura wrote: ↑Wed Feb 05, 2025 6:29 am
No, I'm in IT, but I worked in this field and some of my colleagues where such folks.
Chizakura wrote: ↑Wed Feb 05, 2025 6:29 am
Actually, it won't take much energy. Have you ever tried it? Really, heat your home to 20 degrees and keep it like that for a day. Then open everything for just 1 or 2 minutes and close it again. You will see that you'll get to almost 20 degrees indoor room temperature quite quickly even if your AC is not running. If you don't believe it, try it. The reason is that your walls, floor, roof store multiple times the heat than what the whole air in your home can store. To be more specific, one liter of concrete stores 1500 times as much heat energy than one liter of air. 1500! That means to cool down one liter of concrete from 20 degrees to 10 degrees takes 1500 liters of air that is 0 degrees cold.
I can't quite believe that 100% of the air would be replaced in one or two minutes, unless it were blowing a gale outside, but I take your point. Actually our walls are made of wood, not concrete, so not sure how much heat they can retain.
It depends on the wood of course, but most types of wood store even more heat than concrete, due to the amount of water. Which is btw also the reason why wood is comparably safe against fire, because unlike most people assume, it doesn't just burn - all the water has to be heated up to evaporate first before the wood starts burning and that takes tons of energy.
Just to add onto that: getting one liter of cold water to boil takes about 50000 times the electricity compared to heating one liter of (rather dry) air by 20K (= bringing outside air in winter up to room temperature).
It depends of course on how dry the air is and how efficient the AC is. It can easily vary from 20000 to 70000. Still, that is something that most people don't understand - the order of magnitude is absolutely different. So basically, heating up the freezing winter air of regular 20sqrm room (after completely airing out the room) with AC will take roughly as much energy as bringing 1 liter of cold water to start boiling.