I've noticed a problem in my apartment that returns every winter - I get mold around the windows. This year the cold weather came earlier than usual and the mold appeared quickly in great amounts, so I am looking for a way to at least reduce the thickness of it.
My guess that the molds cause is the humid air would be the fact that very often I can see a condensation on the window, and, since the windows are plastic ones, I guess they don't "breathe" like the wooden ones would.
I've heard about putting bowls of salt around by the windows that would attract the moisture, but some suggest other substances like silica gel since they absorb the moisture better. Problems I see with getting silica gel are that I'm not sure where to get it for starters, am not sure about the price - whether it wouldn't be too pricy and, since I own a cat, I don't want the little adventurer to try out new things to eat - how would I store it so it would do it's job and not harm my pet.

I mentioned "without a dehumidifier" in my question title because buying one just isn't in my budget at the moment, so I'm looking for some temporary solutions right now.
Any tips gladly appreciated.

  • 3
    simplest way? bring in outside cold dry air and heat it up, while venting the warm moist air to the outside Commented Oct 27, 2014 at 12:55
  • The problem is, how are you going to recharge the silica? Put it in the oven, of course, heat it to 250, water gone, silica dry and ready for reuse. wait, where did the water in them go? It vaporized in the oven, interchanged with house air, and it's back on the house. Sigh. Commented Jul 4, 2017 at 4:19
  • See this article about mold from the CDC. cdc.gov/niosh/topics/indoorenv/mold.html I think that your humidity problem is larger than putting bowls of salt or other desiccant out. One thing to explore is where the humidity is coming from, bathroom or kitchen or where and how the source can be changed to reduce the humidity for instance an exhaust fan for a bathroom. Commented Jan 12, 2022 at 23:55

5 Answers 5


You can purhcase products such as DampRid. It is availabe in various size packages and will work to passively dehumidify a space.

You do not want to use a fan or any active air mover to attempt to dry the window space. This can enable the mold to spread to other areas.

Mold is dangerous to your health and this issue should be handled soon. One point of concern is that the mold may be in the drywall surrounding the window. The mold issue should be brought up to your building manager. If they do not take corrective actions, you should speak to the local public health department.

  • 2
    A couple of things: not all mold is dangerous, and not using any sort of active air movers also has the potential to spread spores anywhere. Even something as trivial as OP's cat walking around will help move air.
    – alt
    Commented Oct 27, 2014 at 16:03
  • +1 for taking the issue to the building manager. Mold is not supposed to be able to grow in a living space, whether it's inherently dangerous or not. Moving air toward the windows will help though (after they have been cleaned) since it will prevent the temperature of the wall/frame from dropping below dewpoint. Having to do this constantly is a PITA though and not a real solution.
    – Jeff Meden
    Commented Apr 3, 2015 at 14:37

Your problem is probably caused by the steam from showering condensing on and around your windows.

I would recommend keeping the bathroom door closed while you shower and turning the exhaust fan on while you shower and for at least a half hour after. This will greatly reduce the moisture in your apartment.

On warmer days it would also help to crack your windows open and get some cross ventilation for a while.


You can buy an air ioniser and purifier which they should be much cheaper and smaller than most dehumidifiers. It reduces the level of humidity in the air. Also it will remove pollutants from the air such as dust, mould, mildew, bacteria, viruses, fumes, fungus, pollen, odours, fibres, smoke, soot and other microscopic airborne particles. In addition, pre-filters used to remove larger particles such as hair or fur before they arrive at the main filter (in your case, cat fur).

There are also ioniser air purifier bulbs which works in similar way. It attract smoke, dust and other chemicals which settle on the bulbs.

To find the source of the problem, you may try thermal imager (e.g. Flir One) which can help you isolate places of possible cold leaks around the windows.


Use sponges soak with salt water and let dry. Then put sponges near windows which will absorb excess water. It is old family trick we have used for many generations now.


This is the classic case of condensation problem. My guess is that PVC windows haven't been placed on your building originally, but something you put recently. The other problem (I'm guessing) is that you have no thermal insulation on outside walls or it poor. Furthermore jambs around your windows are most probably faulty. All of this has contributed to your problem. Also, like you said these windows don't act like wooden ones which add up to your problem. Firstly, remove the entire mold; use some chemicals to disinfect that area. Next thing fix the jambs (I'm guessing that they are faulty).Use Styrofoam 1-3cm thick. Now, if you don't have thermal insulation on façade walls, and you can't afford to put it on whole façade or if you are living in a building, you can put some Styrofoam or something similar from the inside on these walls and then repaint the wall (not just repaint put whole preparation procedure).This should fix your problem. Also, try to keep your windows opened as often as possible.

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