Triple glazing and mold?

You forgot to heat properly. If you have cold walls and only 20 degrees warm air, everything will condense on the wall. Especially in the bedroom, this can be a problem because people don’t heat as warmly there.

Thank you, so that means even if the hygrometer shows a good humidity level, e.g. 40%, mold can still occur?

Thanks, so that means even if the hygrometer shows a good humidity level, e.g. 40%, mold can still occur?

At 40% humidity and 20 degrees, the dew point is at 6 degrees - your exterior wall surface should therefore be warmer. 6 degrees is already difficult to reach - even in old buildings. At 60% (bedroom for two and door closed) and 18 degrees, it's a little over 10 degrees.

You can calculate it online.

Especially in the bedroom this can be a problem, since people don’t heat so warmly there.

Do "people" do that? I only know it to be around 20-21 degrees and then also in a 30-degree waterbed. "People" don’t have to sleep cold - 18-20 degrees are completely fine.

We have a corner with the problem that a cantilevered concrete part from the balcony brings in the cold and then mold forms. I don’t want to spread panic now, with 40% humidity it’s not a big problem, but you first have to get it down that far. I find airing out during calm weather (Lake Constance = dead calm spot) quite difficult. There is simply too little air exchange, even if we ventilate through the entire apartment (the bedroom only has windows on one side).

Hello everyone,

I currently still have an old building with only minimal insulation.

The U-value of the facade is 0.965 W/(m²K).

Now, I have very many, very large window surfaces in the house; the south side is almost only windows at the top and bottom. These windows are of course very expensive, and only with triple glazing could I receive a subsidy here.

However, most of these new windows have a lower U-value: 0.81 to 0.93. Is there a high risk of mold developing here? Should one rather opt for double-glazed windows?

I would advise anyone who replaces windows in an existing property to always ensure sufficient ventilation. Everything else simply does not work. We currently have an apartment built in 1999, well insulated, and in winter we have to ventilate at least 4-5 times a day. This is incredibly annoying, especially when it is a bit windy and the doors slam or everything flies around! So don’t skimp on such a small thing. There are windows with integrated ventilators (window rebate vents); maybe that is an alternative. However, I have no experience with them.