RetireJapan

Hi all....

We moved into a mansion and there are two vents in our living room. i found a similar image online and attached here.

My question is...is there any way for me to reduce the amount of freezing cold air coming in? I can push on the vent cover and it "closes", but still more air seeps in from the vent that way. Maybe that is a problem? I was thinking of covering it up on the outside, at least overnight during the winter, but wasn't sure if that is a good idea. Before this mansion, i lived in apartments in Kyoto and in Tokyo, and they had similar vents, but i could actually push them close and very little, if any, air would come in.

thanks for any suggestions or help!

Using electrical tape in a similar color, you could seal that on the outside with four short strips. The tape comes in different widths, the 2cm width will probably work well.

Make sure the surface is clean and dry. Eg, wipe well with a wet paper towel, let it dry, then tape.

You might be able to put in a plastic barrier if the tape idea doesn't work. There are also disposable filter covers available which have tape on the edges.
Something like this:
https://myhome.yanau.info/wp/hd0049/

On an adjacent topic, our 20yr old bathroom exhaust fan was really noisy and some lube didn't solve the issue.

Replacing it was a 15-minute YouTube study and 15-minute installation. Total cost ¥5,000.

Hi...

Thanks for both answers! I will go to the local home center and see about tape or some sort of cover.

I appreciate the help!
...

TJKansai wrote: ↑Fri Jan 31, 2025 1:52 am You might be able to put in a plastic barrier if the tape idea doesn't work. ...

Yeah, if there's removable filter/bug screen built in as a part of the tube at the end(s) or middle, then removing that, wrapping it in kitchen wrap or a plastic bag, and then putting it back in would do about the same thing. (or do this and the tape)

I have vents similar to these in our house in Hokkaido, and the guy who built the house says it's OK - in fact advisable - to close them in winter. However, there is a fan running 24 hours a day that pulls air in from the outside through these vents and exhales it through other vents in the ceiling. Good in summer perhaps but a bit ridiculous in sub-zero winter. There is no switch and no plug for this fan and we've been told NEVER to disable it! This begs the question: when the inlet vents are closed in winter, how the heck does the fan draw air in to replace the air it exhales? Through the windows and walls perhaps? It's a bit of a mystery. Anyone have any experience with these kind of systems?

northSaver wrote: ↑Fri Jan 31, 2025 4:23 am I have vents similar to these in our house in Hokkaido, and the guy who built the house says it's OK - in fact advisable - to close them in winter. However, there is a fan running 24 hours a day that pulls air in from the outside through these vents and exhales it through other vents in the ceiling. Good in summer perhaps but a bit ridiculous in sub-zero winter. There is no switch and no plug for this fan and we've been told NEVER to disable it! This begs the question: when the inlet vents are closed in winter, how the heck does the fan draw air in to replace the air it exhales? Through the windows and walls perhaps? It's a bit of a mystery. Anyone have any experience with these kind of systems?

I read somewhere that if you close the inlet vents in winter, it will make it more difficult to open doors and such, due to air pressur build up.

In any case, it will be good to make sure that the ducts are working when the weather turns warmer unless you want mold growing in your house.

House ventilation systems in Japan
https://living.rise-corp.tokyo/house-ve ... n-systems/

You've gotta close those vents. They for people who are too stupid to air out by hand on a regular basis. Also, you've gotta disable any of those 24/7 running fans. Absolutely stupid nonsense. At least in winter and summer.

Just air out your apartment 3-4 times per day. Once when waking up, once when going to bed and at least one time in between. All the air should be exchanged, so depending on your floor plan and number of windows, in winter that can take just 3 minutes or 15 minutes if you have only balcony doors.

Whenever you take a shower/bath or do cooking/boiling water or increase the air humidity a lot in other ways, you should of course air out as well. And when you take a shower, keep the door open and turn on the ventilation for an hour - and then after half a day, turn it on again for an hour.

That will save you tons of energy and make your apartment more comfortable.

Japanese government *should* actually mandate that all newly build apartments come with heat recovery systems instead of those stupidly dumb holes in the wall that they call vents - but yeah, one can dream...

ChapInTokyo wrote: ↑Fri Jan 31, 2025 4:38 am

northSaver wrote: ↑Fri Jan 31, 2025 4:23 am I have vents similar to these in our house in Hokkaido, and the guy who built the house says it's OK - in fact advisable - to close them in winter. However, there is a fan running 24 hours a day that pulls air in from the outside through these vents and exhales it through other vents in the ceiling. Good in summer perhaps but a bit ridiculous in sub-zero winter. There is no switch and no plug for this fan and we've been told NEVER to disable it! This begs the question: when the inlet vents are closed in winter, how the heck does the fan draw air in to replace the air it exhales? Through the windows and walls perhaps? It's a bit of a mystery. Anyone have any experience with these kind of systems?

I read somewhere that if you close the inlet vents in winter, it will make it more difficult to open doors and such, due to air pressur build up.

Only if something like 24/7 ventulation fans are running. Which should be avoided. Also, IF the doors are harder to open, that's a good sign. Means your apartment is rather air tight. It's the case for my apartment. Honestly, I don't care, then the door is a bit harder to open - no problem with that at all. Maybe for 90yo baachan it is an issue?

ChapInTokyo wrote: ↑Fri Jan 31, 2025 4:38 amIn any case, it will be good to make sure that the ducts are working when the weather turns warmer unless you want mold growing in your house.

It would be good to NOT do that. Keep the ducts shut in summer and put your AC into dry-mode.
Think about it: you want to reduce humidity inside to prevent mold right? You do that by having your AC collect the water in the air and pump it outside - that's what it is made for. If you keep your ducts open, you are basically making you AC collect the water of the outside air all the time. A waste of energy and less effective against mold. The only reason to get in fresh air in summer is to keep CO2 levels low. There is literally no other reason.

ChapInTokyo wrote: ↑Fri Jan 31, 2025 4:38 amHouse ventilation systems in Japan
https://living.rise-corp.tokyo/house-ve ... n-systems/

Better something like this: https://passivenergie.co.jp/en

Chizakura wrote: ↑Fri Jan 31, 2025 5:25 am

ChapInTokyo wrote: ↑Fri Jan 31, 2025 4:38 am

northSaver wrote: ↑Fri Jan 31, 2025 4:23 am I have vents similar to these in our house in Hokkaido, and the guy who built the house says it's OK - in fact advisable - to close them in winter. However, there is a fan running 24 hours a day that pulls air in from the outside through these vents and exhales it through other vents in the ceiling. Good in summer perhaps but a bit ridiculous in sub-zero winter. There is no switch and no plug for this fan and we've been told NEVER to disable it! This begs the question: when the inlet vents are closed in winter, how the heck does the fan draw air in to replace the air it exhales? Through the windows and walls perhaps? It's a bit of a mystery. Anyone have any experience with these kind of systems?

I read somewhere that if you close the inlet vents in winter, it will make it more difficult to open doors and such, due to air pressur build up.

Only if something like 24/7 ventulation fans are running. Which should be avoided. Also, IF the doors are harder to open, that's a good sign. Means your apartment is rather air tight. It's the case for my apartment. Honestly, I don't care, then the door is a bit harder to open - no problem with that at all. Maybe for 90yo baachan it is an issue?

ChapInTokyo wrote: ↑Fri Jan 31, 2025 4:38 amIn any case, it will be good to make sure that the ducts are working when the weather turns warmer unless you want mold growing in your house.

It would be good to NOT do that. Keep the ducts shut in summer and put your AC into dry-mode.
Think about it: you want to reduce humidity inside to prevent mold right? You do that by having your AC collect the water in the air and pump it outside - that's what it is made for. If you keep your ducts open, you are basically making you AC collect the water of the outside air all the time. A waste of energy and less effective against mold. The only reason to get in fresh air in summer is to keep CO2 levels low. There is literally no other reason.

ChapInTokyo wrote: ↑Fri Jan 31, 2025 4:38 amHouse ventilation systems in Japan
https://living.rise-corp.tokyo/house-ve ... n-systems/

Better something like this: https://passivenergie.co.jp/en

Yeah well, I hope you’re right. What do those pesky Japanese architects know about sick building syndrome and PM2.5 and the superiority of opening windows over 24/7 ventilation systems, eh?