VMC: the pros and cons, advantages and disadvantages

Heating, insulation, ventilation, VMC, cooling ... short thermal comfort. Insulation, wood energy, heat pumps but also electricity, gas or oil, VMC ... Help in choosing and implementation, problem solving, optimization, tips and tricks ...
phil53
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Re: VMC: the pros and cons, advantages and disadvantages




by phil53 » 24/10/18, 15:47

It depends on the type of filter 6 month 1 year.
There is the possibility of the remote filter and the maintenance contract for rental companies or schools
They did tests, they arrive down the radon rate in granite buildings.
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Re: VMC: the pros and cons, advantages and disadvantages




by jeanvert » 03/01/20, 23:20

Hello,

It seems to me that the losses by extraction from a single flow VMC are greatly underestimated. The formula that is found conventionally, for example in
https://www.thermexcel.com/french/energ ... _12831.htm
or,


Corresponds to a perfectly dry outside air intake.
With a minimum regulatory flow of 75m3 for a 3-room apartment, the energy extracted is equivalent to:
With dry outside air at 0 ° C, loss by extraction 525 W
With dry outside air at 10 ° C, loss by extraction 262 W
I know that the energy is expressed in Joule which corresponds to a power of 1W during 1s, but the W is more speaking for many

If we take into account that the outside air is humid the figures explode !!
With saturated outside air at 0 ° C, extraction loss multiplied by 3.7
With saturated outside air at 10 ° C, extraction loss multiplied by 4.8
We see that the arguments on the low consumption of CMVs are more marketing because the gains are one to 2 orders of magnitude lower than the losses !!

If you want to check, here are my sources:

https://fr.wikipedia.org/wiki/Capacit%C ... _volumique

https://fr.wikipedia.org/wiki/Capacit%C ... e_massique

https://fr.wikipedia.org/wiki/Masse_vol ... de_l%27air

www.thermique55.com/principal/airhumide.pdf

I made some approximations and I am not immune to a big mistake, knowing that I have been a retired doctor-engineer for several years and that we quickly forget !!!
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Re: VMC: the pros and cons, advantages and disadvantages




by Juju64 » 25/04/20, 15:20

Hello,

Ventilation is a logical development: before we had colanders, houses that let heat and air pass, then we insulated and caulked for energy savings (and that's a good thing) but we didn't ventilate no, many humidity and respiratory problems and the discovery of VOCs in a bunch of products (furniture, paint, glue, PVC ...) have led us to make our homes more breathable and to add ventilation. Like that, we always had energy savings but more problems linked to the lack of ventilation.

If you have an old house, not insulated, then yes mechanical ventilation is not useful, air passes everywhere, hence the big consumption in heating.
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Re:




by Joe Flachy » 20/09/20, 22:36

bham wrote:In the past there was indeed no VMC because the houses were not insulated […] So the walls no longer "breathe", it was necessary to find a stopgap and it was the VMC. […] It was their own insulation, very permeable to water vapor and humidity-regulating.


I moresoie, the problem of excessive ambient humidity is due to the choice of interior materials or their treatments: plasterboard vs plaster, "lino" vs parquet, acrylic vs natural paints and even vitrified vs waxed parquet do there is nothing left to regulate the humidity that has expired.

The old windows were certainly not waterproof, but they weren't strainers either. The difference does not come from there.

We can surely do without VMC by introducing suitable materials, such as raw earth.
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Re: VMC: the pros and cons, advantages and disadvantages




by thibr » 21/09/20, 18:56

there is also the top, the thermodynamic VMC
https://www.mydatec.com/fr/principe-vmc ... ca-marche/
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Re: VMC: the pros and cons, advantages and disadvantages




by LOGIC12 » 30/03/21, 06:20

hello, To do without a CMV, you should not cook in the house, do not take a shower, do not dry clothes in the house, do not have green plants, no aquarium etc ... and old windows that let in a little air.

Personally, in a house from 1975 (beginning of the insulation) I do not have a CMV. There was not originally. The walls are made of concrete blocks, then 5 cm of LV which has not moved, and against a 5 cm brick partition. The house is very healthy, but I have an extractor hood which is used when cooking, but also 5 minutes from time to time as "occasional CMV" with a higher flow rate than a CMV. I also installed a good extractor at the top of the shower, it works during the shower and still at least 2 hours after. And I have another extractor in the WC that works on the light (WC without window). So no problem. The ceilings are at 2,60m, that's a little more volume to heat, but more air to breathe too.

Counting on the walls, the floor etc ... to pump the excess humidity which can be important, that is to say having blotting walls, that hardly enchants me. And with compulsory insulation these days, that's hardly possible.

And remember that in order not to breathe too much polluted air, it is better for it to be renewed, but I recognize that sometimes the CMVs really suck a lot, and especially when there is no one at home and no laundry. to dry.

When the hygro CMVs, I do not understand how they could save money since as soon as the weather is wet, they always pump thoroughly.

There would be improvements to be made.
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Re: VMC: the pros and cons, advantages and disadvantages




by A.D. 44 » 30/03/21, 08:39

Hello,

LOGIC12 wrote:... I have an extractor hood which is used when cooking, but also 5 minutes from time to time as "occasional CMV" with a higher flow rate than a CMV ...


With the scent of toilets that delicately stimulate the nostrils of the cook and the guests !!!

Hmmmmmm
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Re: VMC: the pros and cons, advantages and disadvantages




by A.D. 44 » 30/03/21, 08:43

LOGIC12 wrote:...The ceilings are at 2,60m, that's a little more volume to heat, but more air to breathe as well...


It is on realistic !!!
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Re: VMC: the pros and cons, advantages and disadvantages




by izentrop » 30/03/21, 10:02

thibr wrote:there is also the top, the thermodynamic VMC
https://www.mydatec.com/fr/principe-vmc ... ca-marche/
Double flow VMC incorporating a reversible heat pump.
The best would be that it is eligible for the heat pump premium. ?

Otherwise permanent consumption, not great: 650 W for 250 m3 of renewed air, while a simple low-consumption flow consumes 15 W on average for a maximum flow of 276 m3 which does not require any maintenance https://www.domomat.com/28601-kit-vmc-e ... 33034.html
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Re: VMC: the pros and cons, advantages and disadvantages




by LOGIC12 » 30/03/21, 10:18

hello, AD 44, you must read well, in the toilets there is a good extractor which starts up at the same time as the lighting and there is even a timer which makes it run for another 5 minutes, even.

In addition, toilets, if they are properly maintained, there are fewer germs than in a sink ...

And also, if there are 4 or 5 people in a small area, a larger renewal is needed than in a 120m2 house with two people. But it seems to escape you completely.

And when there are blotting walls, the odors of poorly maintained toilets permeate the walls, the grease from the kitchen makes a layer on the walls, the house is very rotten, but you don't mind ....
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