VMC: Hygro A or Hygro B

[anigel]

Hi,

I read a lot here and on another forum ecological oriented, but a question remains ...

I am in the typical case of a bad choice of renovation: just before the sale of the house the old owner changes the windows for Tryba PVC, perfectly waterproof. Result: after a few years on site it becomes urgent to ventilate (appearance of mold).

The works are launched, and we opted for a very efficient electrically speaking model (I table on 10W maximum consumption). It is a Hygro B extraction kit. The model is designed to work either in Hygro A or B.

The question of mouths arises then. I am offered self-adjusting (type A) and humidity-sensitive (type B?). The price difference between the 2 is significant (+ 250 € for 5 windows treated).

I admit that I lean a priori for a solution in Hygro A, intuitively I tell myself that the VMC unit adapts its speed to the need communicated by the extraction vents, which they are "hygro". So depression induces the speed or not of renewal.

But I wonder: what impact on the cost of heating? To locate: pellet heating on water radiator circuit. Surface 120 m². Hygro A air inlet with a flow rate of 22 m3 / h, variable hygro B inlet from 8 to 40 m3 / h, all in Limousin in a clearly humid area (several ponds nearby) ...

If people well versed in the field can enlighten me on the profitability of the passage on mouths Hygro B, thank you in advance !!

[SixK]

I got interested in the question a little less than 1 year ago.

My conclusions are as follows:
The hygro-adjustable CMV is just a basic CMV with a humidity sensor that engages the 2nd speed when a humidity threshold is reached at the CMV level.

Personally I have a mechanical switch with 2 positions, if we took a shower eventually activated 2nd speed ...
In fact, the VMC we tend to cut it, given the air movement we can have with the fireplace insert and the various openings (ventilation, access door to the garage which lets a good net pass of air)

Then hygro B or hygro A, the difference is just mouths that open more or less depending on the humidity.

In my case, I replaced the ventilations of the windows with fixed flow by hygro-adjustable, because some days, that made sacred drafts.

Incidentally, in this regard, if someone knows the standards in this area, I am not sure that putting 2 windows one in front of the other with 1 ventilation each is something very appropriate? (draft, feeling cold). I hesitate to plug 1 of the 2 ....

For the suction vents the old owner had put round vents with adjustable flow by rotating the central part (things that are no longer done, but that do not seem too stupid and not too ugly) ...
I have adapted the opening according to what I think is necessary for the ventilation of the different rooms.

The only place where a vacuum outlet with automatic flow can be useful is the bathroom.

My advice, but everyone sees according to their house and their needs or estimates. I am not a specialist.
a good basic 2-speed VMC with switch (Sauter 89 Euro in my case) + hygro air intake on the windows (around 30 Euro each) + possibly an automatic mouth for the bathroom. (around 50 Euro it seems to me)

Another point, pay attention to the way in which the VMC consumption is calculated.
I saw the case of skipping (from memory) 25W over 1 day and a DIY brand deposit 12,5W over 12 hours. Brief Scam !!!

Finally, be careful that mold does not come from a thermal bridge. Example with my parents, at the level of the framing of a window it seems to me, installation of a piece of aluminum without insulation underneath. In this kind of case, I think that even when ventilating, it ends up moldy.

Last point, do not hesitate to buy a hygrometer like that, you will immediately see if the house is wet or not ...

SixK

[ATE.Conseil]

Incidentally, in this regard, if someone knows the standards in this area, I am not sure that putting 2 windows one in front of the other with 1 ventilation each is something very appropriate? (draft, feeling cold). I hesitate to plug 1 of the 2 ....
SixK

Hello,

Indeed, the interest of the Hygro B compared to the Hygro A is that suddenly, the house is less subject to parasitic air inlets (in any case by the VMC) and that the automatic triggering of VMC is more precise than the manual switch.
Regarding the flows to install:

- 45m3 / h in night rooms
- 90m3 / h in living rooms

Greetings

[Forhorse]

Another point, pay attention to the way in which the VMC consumption is calculated.
I saw the case of skipping (from memory) 25W over 1 day and a DIY brand deposit 12,5W over 12 hours. Brief Scam !!!
K

Power or energy? W or Wh? don't confuse the two, because that doesn't mean anything.

[anigel]

Hello,

And thank you for your answers ; but I'm not sure I understand ...

Hygro A or B: the group and the outlets are identical (and therefore: hygro-adjustable).

Hygro A: the inlet vents are self-adjusting. Does this mean that the flow is fixed, whatever the external conditions? Or do they adjust to a different measure of humidity? If yes, on what criteria?

Concretely: the VMC will suck mainly according to the flow allowed by the outlets, right? The flow of the inlet vents will it not therefore be controlled by the depression created by the VMC? Which will be "piloted" by the opening of the outlets which are hygro? And if so, is it really useful to have all-hygro? Is it really worth 250 € more?

Or more likely something escapes me and I write anything?

We look forward to seeing you!

[SixK]

I will try to summarize what I said.

for me (I could be wrong),
a VMC is 2 speeds, whether the vmc is hygro or not. indexing the flow on the hygrometry could have been intelligent, but that does not exist.

the hygro air inlets adapt the opening according to the humidity using a kind of paper that stretches or stretches depending on the humidity.
minimum flow 6 m3 / h instead of 40 m3 / h for a grid.

For extractors, I have a doubt, but it seems to me that there are only 2 positions normal flow and large flow. some are mechanical with an ugly thread hanging down. others electric with batteries.
some may be based on the same system as the hygro air inlets, but I don't think so.

In my case, colander house equipped with manually adjustable flow vents, I did not consider it useful to take hygro except for the air inlets.
investment 89 euro + 2 * 30 euro.
For an over-insulated house, with humidity problems, hygiene may be of interest, but I am not particularly convinced. If the CMV runs 24/24, there should not be too many humidity problems.
if there are, then it is better to review the insulation, thermal bridges and possibly the space between the doors and the floor. the air must be able to circulate.

otherwise the consumption unit is W-Th-C.

SixK