ᐅ Air Too Dry! – Should I Replace My Old Ventilation System with an Enthalpy Recovery Ventilation System?

Dear forum,

We have been living in our well-insulated KFW55 house with a controlled mechanical ventilation system for 2 years now. In winter, the indoor humidity sometimes drops to as low as 20%. I would like to change that!

Unfortunately, our current controlled ventilation system does not include an enthalpy heat exchanger, and it is not possible to retrofit one. Therefore, we are considering replacing the ventilation system. This would cost around 5,000 euros.

Is the effort worth it? Can we expect the indoor humidity to increase significantly after the replacement? What humidity levels can we roughly expect following the upgrade?

I wouldn’t do that.
I would even have to replace the heat exchanger for about 600-700 EUR, but I’m holding off on that for now.
However, I don’t particularly suffer from dry air.
We have a lot of houseplants, and that gets us to about 25%.
Maybe that could be an option for you?

What kind of device is currently installed?
In winter, it could also be set to a lower level.
Have you already tried increasing humidity by drying laundry indoors, using humidifiers, or air washers?

Maybe it helps to regularly ventilate through the windows? We have a KfW55 standard, but no mechanical ventilation system, yet we always maintain a comfortable humidity level of 40-50%.

motorradsilke schrieb:

Maybe it helps to simply ventilate the windows regularly? We have KfW55 standard, but no mechanical ventilation system, yet we always have a comfortable 40-50% relative humidity.

Of course that’s possible. But if you’re spending 10,000 euros or more, you usually don’t install a mechanical ventilation system just to end up opening the windows anyway.

Better to use a humidifier instead.

Hendrik1980 schrieb:
We have been living for 2 years in our well-insulated KFW55 house with controlled mechanical ventilation. In winter, the indoor humidity sometimes drops to only 20%. I want to change that!

I feel the same way. I don’t feel comfortable in such dry air.
Your idea of a heat exchanger is consistent, and the cost is definitely worth it if it helps you feel comfortable in your own home. I would calculate (or have someone calculate) how effective the measure really will be. It’s possible that you might still need to ventilate or use additional humidification.

nordanney schrieb:
But generally, you don’t install a controlled mechanical ventilation system for 10k or more just to end up opening the windows anyway.

That’s funny. For comfort, I’ll open a window anytime—no matter how much the heating system cost.