ᐅ Excessive indoor humidity. 60-70% during winter months.

Created on: 29 Dec 2017 14:10
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bpe87
Good day,

I am new here and hope you can help me (even though I am not currently building myself):

We recently moved into a newly painted apartment on the third floor; the building was constructed just before the turn of the millennium.

I noticed that the windows, especially in the mornings in the bedroom, office, and kitchen, are fogged up on the inside edges and have visible water droplets. The windows are partly older wooden windows and partly skylights with metal frames.

I then bought two thermometers/hygrometers from TFA and placed them in the bedroom and kitchen. The humidity levels were between 60-70%.

I have read up online and gathered a lot of tips. We ventilate at least twice a day, usually more often, by fully opening windows for 5-10 minutes maximum, with heating off during this time. The temperature in all rooms is between 19 and 20°C (66-68°F). Laundry is not dried inside the apartment; after showering and cooking, we also ventilate thoroughly and turn on the extractor fan, as well as when the washing machine is running.

Although we notice that during ventilation, the humidity drops to around 40-45%, it rises again within minutes to at least 53% and then slowly moves toward 56-60%. In the morning, the bedroom is about 63-68%, and the kitchen 61-67% (humidity even goes higher during cooking despite ventilation).

We have moisture-absorbing granules in the kitchen and bedroom, but unfortunately, they haven’t made any improvement.

I did not experience this problem at all in my previous apartment and am currently unsure what to do. I plan to start documenting this in writing and then address it with the landlord, but I wanted to ask here first if anyone has any further tips on what I might try.

Thank you very much.

Best regards,
bpe87
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Knallkörper
30 Dec 2017 18:59
From my perspective, you also need to keep heating and ventilating. When the outside temperature is low, it doesn’t matter whether it’s raining or not. Moisture is contained in the floors, walls, doors, and furniture. Based on your description, I also suspect incorrect behavior by the previous tenants. At 19°C (66°F) inside the apartment, you might still not get below 50%, which should not be problematic. We are happy if the humidity in our new building doesn’t drop below 40%, as that already becomes uncomfortable.
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Bieber0815
30 Dec 2017 20:57
bpe87 schrieb:
I aired the room and the humidity dropped to 42.3% at 18.1 degrees, but then within 5 minutes it rose back up to 57% and continued to rise more slowly.

18.1°C (65°F) / 42.3% RH / 5.4 g/kg absolute humidity
18.1°C (65°F) / 57.0% RH / 7.4 g/kg absolute humidity

If your measurements are correct, there was a quick additional input of moisture into the indoor air (showering, cooking, breathing, ..., wet surfaces).

I agree with the majority of advice:
Heat a bit warmer (21–23°C / 70–73°F), ventilate frequently with short bursts, and keep monitoring.

In my opinion(!) it is not possible to soak walls through improper behavior. In such a case, I would rather suspect a damage issue.
77.willo30 Dec 2017 21:31
The rapid drop and quick recovery are due to the humidity sensor having a completely different response time than the thermometer, which is used for compensation, not because of a rapid increase in moisture.
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Baumfachmann
11 Jan 2018 00:49
We experts really have a hard time with you.
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bpe87
12 Feb 2018 23:44
Hi,

I wanted to check in again.

By now, the room temperatures fluctuate between 20-21°C (68-70°F). The humidity level is around 50-55%, so it has improved a bit.

However, even with these values, the windows have been damp on the inside edges in the mornings and evenings over the past few days, with one window even showing widespread moisture. Is this normal due to the cold outdoor temperatures? Is there any way to reduce this?

Best regards
bpe
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toxicmolotof
13 Feb 2018 01:42
Ventilate, ventilate, ventilate... wipe away.