ᐅ 20% Relative Humidity in a KfW 40+ New Build

Hello everyone, the title already describes the problem. Approximately 20% humidity in all living and sleeping rooms. We moved in about two weeks ago. That can’t be normal, right? I expected such low humidity only after 2-3 years, but not right from the start...

The first night in the house was really horrible. On top of that, we have been dealing with colds and coughing the whole time. We now have a humidifier running all night in the bedroom (starting in the evening, about 12 hours total) and wake up with around 35-40% humidity.

Could something be set incorrectly in the mechanical ventilation system with heat recovery, or is this low humidity normal in a new house?

What can we do? Apart from the bedroom, we don’t notice it being a problem in any other room. Enthalpy exchangers are supposed to increase humidity by a maximum of 5%, right?!

Thanks for your feedback and best regards

Without an enthalpy exchanger, this is probably normal.
Why does the humidifier only run in the evening?

Clearly, the alternative is to run it all day. I was hoping for a more technical, comprehensive solution to address the problem.
Enthalpy – does anyone have experience with this? +5% is not that much.

Ypsi aus NI schrieb:

Of course, the alternative is to run it all day. I was hoping for a more technical, overall solution to address the problem.
Enthalpy - does anyone have experience with this? +5% doesn’t seem like much.

We have an enthalpy exchanger and usually get about 55-60%.
Now that it has been very cold and dry for another week, it has dropped to around 50-55%.

I can’t say whether it would only be 5% less without enthalpy.
But I assume the enthalpy exchanger makes more of a difference, and without it, we would probably be closer to 30%. ;-)

Plants. Plenty of them. Not just one per room. Basically, every windowsill needs to be full, and every surface that isn’t a walkway should be covered with plants. This way, we reach about 32% (excluding enthalpy). My wife then takes about an hour to water them, but fortunately, it’s her passion.

I think this can happen at the beginning. My parents experienced the same issue in their new house. They also moved in during winter. Several times a technician came because my mother couldn’t believe that everything was working correctly. The humidity level was a maximum of 30%. It only improved somewhat after they had lived there for two months. Cooking, everyday living, and doing laundry helped the very dry materials to “acclimate” over the first few weeks. I also found it extremely uncomfortable.

What kind of furniture and flooring do you have? My parents have tile flooring throughout the ground floor, where the bedroom is located. With carpets and curtains, it got somewhat better. Now, in the second year, they only use a humidifier in the bedroom.