Ventilation VMC heat loss, a question that grieves me

[the middle]

the air inlets on the roller shutter boxes constantly spit cold air at me.
as for my good brand firm home I have to turn on at 16 p.m. to get hot at 21 p.m.

This is what shocks me in this house, the two info in bold.
1) feel cold air entering through the shutter boxes,
2) it takes 5 hours to heat a house that has almost no thermal inertia, with a 15kw wood insert !, it is completely illogical.
Her house should be warm in 30 minutes.

[I Citro]

1) feel cold air entering through the shutter boxes,
2) it takes 5 hours to heat a house that has almost no thermal inertia, with a 15kw wood insert !, it is completely illogical.
Her house should be warm in 30 minutes.

Indeed.
1) Significant air loss is a big problem. We all know how to close windows when we heat. This must be able to be resolved.
2) If the thermal inertia is not in the walls, it may be in the ground or in large thermal bridges or losses.

An infra-red or infiltrometric camera diagnosis can be useful. I would start by correcting the problems identified.

[chatelot16]

closed chamber "of good brand" is useless information, whatever the brand if something is badly assembled it works less well ... so describe in detail your installation

1st remark: a wood fireplace needs air to work, and absorbs a fairly large flow: it would be logical to put an outside air intake pipe so as not to take in the warm indoor air, and therefore bring in more more cold air through the vents

when a wood heating without cold air intake works we can cut the VMC

but the air flow for combustion is not that huge ... so you may have a worse problem, in the kind of leakage of the hot air distribution: if the hot air recovered in the hood gets lost in the attic instead of being sent to another room, it ruins the heating power, and it causes a big depression in the house with big air intake by all the air vents

[LOGIC12]

hello, To be able to do without CMV, you should not breathe, do not cook, do not shower, do not put clothes to dry inside etc.

Just place a hygrometer in the bathroom whose air has been renewed. We look at the figure before and after the shower (even a short shower barely 37 °).

There we quickly understood.
I have a neighbor who built for retirement. He put a first tenant for 3 years in his new house: everything was fine, nothing to report. He put a second tenant who managed to get mold in this new house.
Of course, there is a VMC, but it must create too much humidity and the VMC does not follow, there is a limit to everything. Note that it never opens the windows, even in summer ...

There was a time when we knew we had to ventilate well, make air flow, and that we did not forget to do it. Nowadays, some people never open the shutters, nor the windows for that matter.
So when we talk about substandard housing, it does not always come from housing.

And with these BBC houses which have a rickety CMV (so as not to let out too much heat) and which only have an extractor hood, some experts rightly think that at the slightest pan of water , the air will be saturated with humidity and unsanitary conditions will follow.

Personally, I only have an extractor hood and an extractor in the bathroom. In the morning I operate the hood fully and I open one window at a time for about 5 minutes.

The hood leaves 300 m3 per hour or 5 m3 per minute, the air in a room is quickly renewed. But not everyone will do that, especially not in rental, where everything has to be automatic.

[Philippe Schutt]

But yes, the lifestyle has changed, for example in the past we hung the laundry on the balcony which is generally prohibited today in the condominium rules, so we have drying racks inside the accommodation, hence a humidity that did not exist.
So some will say "bullshit, let's go back to the old system", except that it is not done, and others will try to adapt the building to new habits, ultimately less of a headache even if in absolute terms it is is to respond to bullshit with reverse bullshit.

Similarly for waterproofing, old houses had watertight walls in themselves, which is no longer the case. We see outside between the bricks, at the junctions with the joinery etc ... When I asked the question to a site foreman, he replied that it was the plaster that provided the waterproofing. In a context of such degraded construction quality, a tightness control became necessary.

A wood fire consumes a lot of air, a large supply of outside air (D 100 or more if long duct) in the immediate vicinity of the fireplace is recommended. In value, we easily climb to 30m3 / h with a good big fire, so the living room is well cooled. But if we spit like that, the T ° of smoke rises briskly to 400-450 °, so whatever the labels say we heat the birds above all. The advertised efficiency is only valid at nominal power, which is by far not the maximum power, generally less than half of this, and at smoke T ° of around 200-250 °. So making a hellfire is not the solution.

At first, I would check that the chimney takes its air outside and not from the room and that the flow of hot air to the vents is sufficient. In 1nd, put humidity sensitive vents and a regulation of the speed of the VMC according to the depression in the sheath. After which your problem should be reduced to an acceptable level. Finally in theory ...

[LOGIC12]

hello, even if the post is old, it can be useful. Here is how to better adapt an air intake compared to the extraction.

The VMC needs as much air to enter as it extracts, but no more as it often does, due to the wind or a large difference between the outside and inside temperature. So here are tips gleaned from the net:

https://www.youtube.com/watch?v=3xgc90h8A4Y

https://www.youtube.com/watch?v=OgZqOi-6RmI

We can always be inspired by it.

[LOGIC12]

Hello,

No risk with Canadian wells and radon.

In fact, the hose must absolutely be watertight, if only to avoid the risk of filling with water. In addition, we draw air from outside

therefore no risk, even if there is radon, it does not enter the pipe.

[Philippe Schutt]

Even if it means putting a filter, I prefer that it be on the suction vents of the VMC rather than on the shutters, so that the housing is not in depression. And if I have the choice of means, I prefer even more to the addition of an electronic regulator on the suction motor, so as not to consume more than necessary.
After all, if I want to drive 100 with a car that goes up to 200, I'm not going to go all out and regulate by braking.

[izentrop]

Even if it means putting a filter, I prefer that it be on the suction vents of the VMC rather than on the shutters

To keep the dust inside?
I also don't see the point of sacrificing a humidity-sensitive air inlet with a piece of host filter. Firstly because dust is unlikely to enter from the top of a window and then we lose the humidity sensitive function.

[Philippe Schutt]

To keep the dust inside?

they are trapped in the filter, therefore eliminated from the air in the accommodation, and limiting the fouling of the VMC pipes seems to me to be correct too.