ᐅ Central ventilation system – is humidity recovery necessary?
Created on: 30 Dec 2019 16:17
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ludwig88sta
Hello everyone,
for our planned single-family house with 2 floors and a basement, we have decided on a central ventilation system for all rooms with heat recovery within the thermal envelope. The brand and model are not yet determined.
I have read here on the forum a few times about an additional moisture recovery feature (MRF?), since otherwise the indoor air tends to become too dry (of course, the ventilation system also removes the moisture that naturally occurs in the room, which usually makes the air feel comfortable). I wanted to ask if anyone can confirm these issues and whether this is more common in timber frame houses or also occurs in brick houses?
Did you install additional moisture recovery in your ventilation system? How much extra cost does it involve? I assume there are also additional maintenance costs because it involves another motor and related components.
Best regards
ludwig88sta
for our planned single-family house with 2 floors and a basement, we have decided on a central ventilation system for all rooms with heat recovery within the thermal envelope. The brand and model are not yet determined.
I have read here on the forum a few times about an additional moisture recovery feature (MRF?), since otherwise the indoor air tends to become too dry (of course, the ventilation system also removes the moisture that naturally occurs in the room, which usually makes the air feel comfortable). I wanted to ask if anyone can confirm these issues and whether this is more common in timber frame houses or also occurs in brick houses?
Did you install additional moisture recovery in your ventilation system? How much extra cost does it involve? I assume there are also additional maintenance costs because it involves another motor and related components.
Best regards
ludwig88sta
L
ludwig88sta10 Jan 2020 21:00Are the Zehnder units being disposed of or returned?
L
ludwig88sta10 Jan 2020 21:47Okay, I didn’t know that. I read it as if it were a new ventilation system. Is it a portable humidifier, and where is it located now?
matte1987 schrieb:
We have a Zehnder Q350 with heat recovery and actually struggled with air that was too dry already during the first winter.I can report almost the opposite for us:We built with solid construction (including the interior walls!) and everywhere there is lime plaster with a grain size of 1.2mm (0.05 inches), except for the bathrooms (where there is lime-cement plaster).
We left the lime plaster untreated because of its vapor permeability and based on the plasterer’s recommendation.
The ventilation system is a Vallox ValloPlus 350 MV-E (with an enthalpy heat exchanger).
The system was set up in half a day with air measurements taken at all supply and exhaust outlets by a technician.
The air exchange rate is about 0.3.
After more than a year of operation, we have at least 50% relative humidity in winter and usually between 70–80% in summer.
Therefore, we ordered a regular heat exchanger without enthalpy online and replaced it before winter (November 20, 2019).
Currently, we mostly have between 50–60% relative humidity.
Last winter it was above 60% at this time.
We hope to get below 50% by the end of winter so that we don’t end up at 70–80% again in summer.
According to the architect, this is partly due to the lime plaster, which absorbs moisture and releases it again.
Attached are the current recordings from this week as well as from the month.
(The peaks are mostly from showering)
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