Hmm, which floor do you find it worst?
I also have same issue as you. The house is very humid if no people around. Use the humidity sensor, the humidity level is close to 80% for the lower floor. And the dehumidifier (the highest spec available for house) can be full within one hour.

Unless you can build a ventilator duct from lower floor to upper floor then to well, else it might not be very effective to relies on the well/ventilator.

For me, I have goes for expensive route by installing Tuma brand ventilator. But my house condition is not as bad as your such that wall is 'sweating'
https://www.tuma.com.my/product.php?cls=3&id=15

At least I no longer relies on the dehumidifer so save on electricity bill but pay high upfront cost.

Yup, which I "kind" of feel that the price is on high end, feel like they should be better option since it really just look like a nicer version of the kitchen wall ventilator floor.

[Maybe something you can consider if you dont mind either ur window or wall got the wall fan look】

Hmm, maybe can compare the humidity in between your outdoor and indoor to see whether the difference are big? Since my case is I validate during the sunny day and the humidity between outdoor and indoor is quite far apart.

Just curious, does switching on fan help in improving the situation? Like using the standing fan or circulation fan.
If can, could be a cheap fix for now till waiting for the sunny season comes where you can see whether the issue is seasonal issue or permanent and decided whether worth for you to do a roof ventilator etc.

This post has been edited by yuen300: Jan 4 2024, 10:22 PM