Hello,
we would like to build a one-and-a-half-story single-family house with about 125 sqm (1,345 sq ft) plus additional development space in the attic. Without a basement but with a 9 m (30 ft) garage.
We have a plot of land in sight, which we hope to reserve by May. We have already had several appointments with construction companies, including TaC, a developer from Krefeld, and one from Sonsbeck. I feel increasingly uncertain. Both developers offer roughly the same concept, but their prices differ significantly. One says that a ventilation system is not necessary for a KfW 55 solid construction house, while the other says it is very important. I am completely confused. Intuitively, the developer from Sonsbeck was our favorite—until we saw the cost estimate.
It is just too expensive! With TaC, the costs are within our budget, but opinions about the company are mixed.
Does anyone have experience in the NRW area?
Best regards
we would like to build a one-and-a-half-story single-family house with about 125 sqm (1,345 sq ft) plus additional development space in the attic. Without a basement but with a 9 m (30 ft) garage.
We have a plot of land in sight, which we hope to reserve by May. We have already had several appointments with construction companies, including TaC, a developer from Krefeld, and one from Sonsbeck. I feel increasingly uncertain. Both developers offer roughly the same concept, but their prices differ significantly. One says that a ventilation system is not necessary for a KfW 55 solid construction house, while the other says it is very important. I am completely confused. Intuitively, the developer from Sonsbeck was our favorite—until we saw the cost estimate.
It is just too expensive! With TaC, the costs are within our budget, but opinions about the company are mixed.
Does anyone have experience in the NRW area?
Best regards
Hi,
Exactly, with heat recovery.
But:
50 watts running 24/7 adds up to about 110 euros in electricity costs per year. Plus the costs for replacing filters twice a year, and we’re easily looking at 200 euros annually.
Plus financing costs of 100–150 euros per year (around 10,000 euros financed at 1–1.5%).
So the total costs are roughly 300–350 euros per year.
Estimated heating demand (based on the old house, which was less well insulated) is around 15,000 kWh. This currently costs about 600–700 euros.
The mechanical ventilation system would have to cut heating costs by half to pay off, and it definitely never does!
Best regards,
Andreas
Caspar2020 schrieb:
Why not? It’s a mechanical ventilation system with heat recovery, right?
Exactly, with heat recovery.
But:
50 watts running 24/7 adds up to about 110 euros in electricity costs per year. Plus the costs for replacing filters twice a year, and we’re easily looking at 200 euros annually.
Plus financing costs of 100–150 euros per year (around 10,000 euros financed at 1–1.5%).
So the total costs are roughly 300–350 euros per year.
Estimated heating demand (based on the old house, which was less well insulated) is around 15,000 kWh. This currently costs about 600–700 euros.
The mechanical ventilation system would have to cut heating costs by half to pay off, and it definitely never does!
Best regards,
Andreas
T
toxicmolotof3 May 2017 16:00My question about the costs was solely related to energy efficiency, not so much to the initial investment costs.
At 50 W/h, we are at 1.2 kWh/day. And with 1.2 kWh, I can exchange all the air in my house twice at 0°C (32°F) outside temperature, completely without heat recovery through the windows.
At 50 W/h, we are at 1.2 kWh/day. And with 1.2 kWh, I can exchange all the air in my house twice at 0°C (32°F) outside temperature, completely without heat recovery through the windows.
Hi,
We have about 670 m³ (24,000 ft³) to ventilate and exchange the air every 3 hours, so 8 times a day.
Best regards,
Andreas
toxicmolotow schrieb:
replace the entire air twice at 0°C (32°F) outside temperature,
We have about 670 m³ (24,000 ft³) to ventilate and exchange the air every 3 hours, so 8 times a day.
Best regards,
Andreas
77.willo schrieb:
... but the horror scenarios here are completely far-fetched. You have ventilation with the window rebate vents anyway, so you don’t need to ventilate manually.
Seal them all airtight and check if your claim that the sensors only activate after showering is true.
If that’s the case, I’ll believe you.
Bieber0815 schrieb:
Why would you do that? Such an inspection is only done when needed, and I don’t see any need here. I can’t see germs, and certainly not what happens inside the pipes.
And that is exactly the main argument opponents use. Everyone speculates about possible germs, but no one has ever proven it. It would be really valuable information for future generations.
No one disputes that a mechanical ventilation system with heat recovery is not cost-effective.
However, we all agree that ventilation is necessary, no matter how it’s done, right? And if you say manual ventilation is enough, then you have to be honest with yourself and do it properly, or use sensors to get a notification—I even find being notified through an app quite practical.
C
Caspar20203 May 2017 16:37toxicmolotow schrieb:
With 50 Wh, we are at 1.2 kWh/day. And with 1.2 kWh you canHowever, this does not take into account that, for example, a Zehnder with heat recovery has an effective heat recovery efficiency (η_HR,eff) of 84%.
When you ventilate, those 1.2 kWh are simply lost. Thanks to heat recovery, they are not. This aspect should not be overlooked.
Typically, 10–20% of energy losses in a standard house occur due to traditional ventilation.
andimann schrieb:
We have about 670 m³ (24,000 ft³) to ventilate and exchange the air every 3 hours, so 8 times per day.I have to say that at first, we didn’t want the mechanical ventilation with heat recovery and only included it because it allowed us to completely eliminate windows in two basement rooms and also saved us from installing solar thermal panels on the roof. This almost covered the entire cost of the ventilation system since I only bought the materials and installed the unit myself. It’s not rocket science.
It has only been running for a few weeks now, and I’m honestly surprised at how pleasant it is. There is comfortable air and optimal humidity everywhere. No more forgetting to close windows after ventilation. Also, there is noticeably less smell of campfire or wood stove smoke in the house compared to when windows were open.
We lived in the house for almost three months before I finally put the ventilation system into operation. It was quite challenging to keep the indoor humidity below 50% during that time, especially in rooms without any ventilation or cross-ventilation possible. And there were always discussions like, “There’s a draft, the child will get sick, etc…”
Annoying!
Now, with the mechanical ventilation, we constantly have indoor humidity between 40% and 45% throughout the whole house, without opening a single window.
We now see the mechanical ventilation as a comfortable “background ventilation” running quietly in the background. After showers or heavy cooking, we still open a window, but much shorter and less frequently than before.
Best regards,
Andreas
It has only been running for a few weeks now, and I’m honestly surprised at how pleasant it is. There is comfortable air and optimal humidity everywhere. No more forgetting to close windows after ventilation. Also, there is noticeably less smell of campfire or wood stove smoke in the house compared to when windows were open.
We lived in the house for almost three months before I finally put the ventilation system into operation. It was quite challenging to keep the indoor humidity below 50% during that time, especially in rooms without any ventilation or cross-ventilation possible. And there were always discussions like, “There’s a draft, the child will get sick, etc…”
Annoying!
Now, with the mechanical ventilation, we constantly have indoor humidity between 40% and 45% throughout the whole house, without opening a single window.
We now see the mechanical ventilation as a comfortable “background ventilation” running quietly in the background. After showers or heavy cooking, we still open a window, but much shorter and less frequently than before.
Best regards,
Andreas
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