ᐅ Controlled residential ventilation with heat recovery — a confusing topic?
Created on: 13 Sep 2014 07:14
V
Voki1
Hello dear forum members,
We are—more or less—at the stage of choosing the general contractor, and now the question of installing a controlled mechanical ventilation system with heat recovery has come up again, even though we had initially decided against it for ourselves.
An appointment with a building expert from the Homeowner Protection Association really challenged my views and reopened the question of whether we need such a system at all.
Just to preempt some of the typical forum assumptions: yes, I have spent a day and a half on this forum and elsewhere absorbing information like crazy. I’m probably wiser, but still not ready to make a decision. It can’t be that I have to roll dice or flip a coin here.
I would really be interested in concrete arguments for why one might be able to do without such a system. For a controlled mechanical ventilation system with heat recovery (Pedotherm / Vaillant), we would have to pay nearly 10,000 euros. That’s quite a chunk. The general contractor did not push for it but clearly said it is not absolutely necessary (if you ventilate really well). However, in our case, there is practically no one home between about 7 a.m. and 4 p.m. That would be rather disadvantageous, especially in the first years of the new build, because window ventilation would naturally be reduced during those hours.
Man, this is quite frustrating when you feel so uncertain. Could you please help provide some reassurance?
We are—more or less—at the stage of choosing the general contractor, and now the question of installing a controlled mechanical ventilation system with heat recovery has come up again, even though we had initially decided against it for ourselves.
An appointment with a building expert from the Homeowner Protection Association really challenged my views and reopened the question of whether we need such a system at all.
Just to preempt some of the typical forum assumptions: yes, I have spent a day and a half on this forum and elsewhere absorbing information like crazy. I’m probably wiser, but still not ready to make a decision. It can’t be that I have to roll dice or flip a coin here.
I would really be interested in concrete arguments for why one might be able to do without such a system. For a controlled mechanical ventilation system with heat recovery (Pedotherm / Vaillant), we would have to pay nearly 10,000 euros. That’s quite a chunk. The general contractor did not push for it but clearly said it is not absolutely necessary (if you ventilate really well). However, in our case, there is practically no one home between about 7 a.m. and 4 p.m. That would be rather disadvantageous, especially in the first years of the new build, because window ventilation would naturally be reduced during those hours.
Man, this is quite frustrating when you feel so uncertain. Could you please help provide some reassurance?
Voki1 schrieb:
The general contractor here did not push for it but clearly stated that it is not strictly necessary (if you ventilate very well). However, in our case, no one is actually at home between about 7 a.m. and 4 p.m. This would be less ideal (in a new build) during the first years, as (shock) ventilation would naturally not take place then.First of all, that is a fairly good statement from the general contractor, which might suggest loyalty to the client.
In principle, a qualified assessment must be made regarding whether natural infiltration plus window ventilation is sufficient to ensure moisture protection (FN).
In very airtight houses, it can almost be assumed that this is not the case, since it is generally necessary to ventilate by fully opening windows at least four times or more per day. A specific calculation can provide an answer to this.
With longer absences during the day, it is unlikely that one will ventilate as often as required during the remaining time. Moreover, humans tend to ventilate just enough to avoid discomfort.
Such a calculation provides information on the amount of available air, the level of natural infiltration, whether a mechanical ventilation system is required, how ventilation affects air exchange (how much air is exchanged within what time and at what setting), and possibly energy consumption or savings and even electricity usage.
If a ventilation system is planned, it must be designed at least at its lowest setting for moisture protection (FN).
Even if this answer may no longer contribute to your decision or simply conveys my perspective, I wanted to leave it here for others at this point.
Similar topics