ᐅ Single-room ventilation and cooling

I am considering adding some improvements to increase living comfort in my home.

My trusted plumber is fully booked, so I would like to hear about your experiences before I get advice from third parties that might not be suitable.

We have a newly built house from 2020 without a ventilation system. (We will be wiser with the next house, but that is not the topic here.)

The only room where we experience comfort issues is the bedroom, which is 15m² (approximately 160ft²) in size. We notice increased condensation on the windows during the colder months, high humidity levels, and a feeling of stale air—(so far) no mold. We would like to install a ventilation system to better control moisture in this room.

During the summer months, additional cooling would be desirable. The system doesn’t need to cool down to 18°C (65°F), but at least provide more comfortable temperatures than last night’s 25°C (77°F).

Which types of systems would be suitable for these needs? So, ventilation, humidity control, and cooling. Or would this require several separate components?

Do you have any recommendations for manufacturers or devices?
Noise levels are important as well, because this is for a bedroom.

A ventilation system does not cool. An air conditioning unit does not provide fresh air (oxygen). So, you need both (exceptions prove the rule).

You might also consider monitoring CO2 levels in the bedroom.

However, I would rather advise against using window fans with oscillation in the bedroom. When the fan runs on a low setting, the gentle noise is not an issue. But because it changes direction every minute and stops and starts again, this becomes disturbing, especially when falling asleep. That’s why we set ours to an 8-hour pause at night.
I would instead recommend a simple fan that just blows fresh outdoor air into the bedroom. Regarding the temperature, I would first look for ways to optimize so that the temperature doesn’t rise too much. If shading during the day and ventilating in the evening are not enough, you will hardly avoid needing an air conditioner.

Osnabruecker schrieb:

The only room where we have comfort issues is the bedroom, size 15m2 (about 160 ft2), specifically increased condensation on the window during the cold months, high humidity, and a feeling of stuffy air – (so far) no mold.

Let me guess. Heating completely turned off in the room during winter, bedroom doors closed.
==> User error. In a new build, condensation on the window is solely caused by user behavior.
==> Proper ventilation and keeping doors open. Set the temperature to a normal level – that’s still comfortable for sleeping.

Osnabruecker schrieb:

During the summer months, additional cooling would be desirable. It doesn’t have to be as low as 18°C (64°F), but at least more comfortable temperatures than last night (25°C/77°F).

What kind of exterior sun protection do you have on your house? Yesterday we had 32°C (90°F) outside and about 23°C (73°F) inside in the evening. At night, with windows open, it dropped below 20°C (68°F). Shutters on the sunny side were closed.

Otherwise, I agree with others: fresh air = ventilation, and cool air = air conditioning.

P.S. Good decentralized ventilators are quiet enough for me at night. I have one installed in my bedroom. The exhaust fans can be adjusted as needed (on/off/supply air/exhaust air/oscillating mode). This means they can be set to supply air comfortably during summer nights. However, retrofitting involves considerable work including core drilling and possibly electrical wiring.

I also have a supply and exhaust fan with heat recovery in the bedroom. We use it exclusively in supply air mode. Not optimal in terms of energy efficiency, but more comfortable at night.