Hello everyone,
maybe someone here can give us a good tip, as we are quite uncertain about a ventilation system.
We are planning to build a house (solid construction) according to KfW 70 standards, with underfloor heating, a fireplace, and a solar system. That much is already decided.
We received an offer from Company A for a ventilation system with heat recovery, and the salesperson recommended it to us.
At Company B, the ventilation system is significantly more expensive, and the salesperson told us that since the house is so well insulated, moisture would not be an issue... where would it come from? The rest could be regulated by normal airing anyway.
(I also think he realized that his ventilation system would have blown our budget and now I worry that he advised us against it just for that reason!)
My husband and I are laypersons, but my instinct tells me that the better the house is insulated, the more problems I would have getting rid of moisture and stale air inside the house, right?
After all, a blower door test does show that there is very little air circulation.
Am I completely wrong?
We are a bit torn now, since such a system is not exactly cheap! But is it necessary, or just a nice extra?
Thank you very much for your help!
maybe someone here can give us a good tip, as we are quite uncertain about a ventilation system.
We are planning to build a house (solid construction) according to KfW 70 standards, with underfloor heating, a fireplace, and a solar system. That much is already decided.
We received an offer from Company A for a ventilation system with heat recovery, and the salesperson recommended it to us.
At Company B, the ventilation system is significantly more expensive, and the salesperson told us that since the house is so well insulated, moisture would not be an issue... where would it come from? The rest could be regulated by normal airing anyway.
(I also think he realized that his ventilation system would have blown our budget and now I worry that he advised us against it just for that reason!)
My husband and I are laypersons, but my instinct tells me that the better the house is insulated, the more problems I would have getting rid of moisture and stale air inside the house, right?
After all, a blower door test does show that there is very little air circulation.
Am I completely wrong?
We are a bit torn now, since such a system is not exactly cheap! But is it necessary, or just a nice extra?
Thank you very much for your help!
I can take a picture showing what the ducts of a mechanical ventilation system with heat recovery look like inside after 3 years of continuous operation... maybe then the fears about dirty pipes will finally end, and building experts who advise against mechanical ventilation systems for fresh air enthusiasts will be proven wrong??? Somehow that seems contradictory, doesn’t it???
Perlenmann schrieb:
@HighDef: Of course, you can justify your decision against mechanical ventilation with heat recovery. But I’m also entitled to share my opinion!
Quick question: Do you ventilate your car too? Aren’t you worried about that?
- I don’t need any additional measures to control humidity in my home.
- What’s so bad about running it continuously? 10 or 15W power consumption on the lowest setting? My heating controllers or timed roller shutters use more!
- Maintenance costs, I can’t deny that. But what do I care about almost 80€ per year if it always provides fresh filtered air?
- Seeing what my filters catch makes me wonder where this high dust level is supposed to come from? Natural ventilation through windows is obviously not the same as moving air! Please name the study if you claim otherwise!
- I only hear my mechanical ventilation on the highest setting, and it’s not even used during the boost ventilation function.
- I can’t really compare noise and fine dust pollution from mechanical ventilation to those from a busy street nearby.Regarding the car:
Only at first glance a good example. In a car, only fresh air enters; there is no extraction, so condensation through the ventilation doesn’t occur. However, the air ducts can get musty with incorrect use of the AC in summer, especially when it runs until the vehicle is turned off.
Regarding power consumption:
Has anyone actually measured it? How can a fan generate such a high air exchange rate through filters at all the valves and in the central unit with only 15W? Either the filters are very coarse, permanently clean, or this power consumption figure seems rather optimistic to me.
Regarding dust:
Neither side should really complain if they vacuum regularly with a normal vacuum cleaner. Logically, you would then have to consider a central vacuum system, which, however, can cause issues when combined with mechanical ventilation.
Regarding acoustics:
This cannot be generalized. It depends both on individual sensitivity and on the placement of the valves. Those disturbed acoustically by airflow would probably also be bothered by phone echo effects in the ductwork and large door gaps, resulting in sound traveling through the house.
I’m very glad to have an architect I know and trust who doesn’t just sell me whatever earns him the most money.
Among people I know, architect-designed houses mostly don’t have mechanical ventilation, while houses planned by general contractors are always equipped with mechanical ventilation... makes you wonder. When you ask why mechanical ventilation was installed, you hear the same arguments over and over... and somehow you get the feeling that maybe people just don’t want to admit they possibly didn’t invest those 12,000–15,000 Euros (about $13,000–$16,000) wisely.
My favorite argument is the calculation that with an exhaust air temperature of 20°C (68°F) and supply air preheated to 18°C (64°F) through the heat exchanger, a 90% heat recovery efficiency is achieved... a perfect case of optimistic accounting.
P
perlenmann10 May 2014 08:58My favorite is hearing the argument from owners without controlled residential ventilation explaining why they do not want controlled residential ventilation.
B
BauProjekt1410 May 2014 09:21Why should an architect profit from a ventilation system?
There are also decentralized solutions. These are less expensive and simply have different advantages and disadvantages compared to a central controlled residential ventilation system.
There are also decentralized solutions. These are less expensive and simply have different advantages and disadvantages compared to a central controlled residential ventilation system.
BauProjekt14 schrieb:
Why should an architect profit from a ventilation system?
There are also decentralized solutions. These don’t cost as much and simply have different advantages and disadvantages compared to a central mechanical ventilation system with heat recovery.
If billing according to HOAI, there is the possibility to do this twice.
They can take into account the "complexity of the system" and the additional effort during tendering through the fee rate. In other words, they fully exploit the fee category.
Furthermore, the billable costs of the project increase, which also brings in more money.
Arnonühm schrieb:
If he invoices according to HOAI, there is a possibility to do so twice... Officially, he does not have any other option with open planning – or does he? Arnonühm schrieb:
...He can take the "complexity of the system" and the additional effort in the tenders into account through the fee rate. In other words, he fully exploits the fee group.... Correct, he "can" and often does. Whether this actually happens in a specific case is unclear. This also applies to the heating system and domestic hot water preparation!
The assumption that future homeowners are naive and get fooled only in general contractor (GC) projects can often also be applied to open planning.
Just take a close look at the detailed wording of the architect’s contract!
Best regards.
Similar topics