Hello everyone,
We are currently starting to deal with the technical aspects of our single-family home.
I haven’t found a thread discussing whether a ventilation system generally makes sense or not. So here is a general discussion thread on the topic:
At first, we looked into various timber frame construction providers, which made us quite sensitive in this area. Naturally, a ventilation system is quite important due to the tighter building envelope, which I can completely understand. However, everything is also marketed accordingly...
Since we have now decided to go with a regional solid construction company, completely different questions arise:
I currently have a detailed offer from a solid construction company:
- $10,000 additional cost for thermal insulation measures
- $13,000 additional cost for a central ventilation system or $9,000 additional cost for a decentralized ventilation system
--> So the repayment subsidy of $18,000 is of little use to me; on the contrary, I am even paying extra for this (of course, I get a “better” house in return).
Key Data:
- Single-family home city villa, 150m² (1,615 ft²) with basement
- Air-to-water heat pump
- Building material: brick
The questions I am now asking myself:
1. Is a ventilation system even necessary to achieve KfW 55 standard?
2. If yes, would it maybe make more sense to go for KfW 70 and forget about the subsidy?
3. Is a ventilation system really that great? There are many reports about noise, high maintenance, etc.
4. If yes, in our building project would a decentralized or central system be better? I have read a lot of positive things about decentralized systems, so central ones might not be an option? Is that correct or not?
5. Is it even possible to reach KfW 55 standard otherwise? Do you really have to ventilate every 2 hours? Are there any experiences?
6. Is the additional $10,000 cost for KfW 55 without a ventilation system justified? Are the prices for the ventilation systems justified?
I know this is an endless debate and there are clearly two opinions here. However, we find it really difficult to make a decision. Maybe a few discussions and information here will help us make up our minds.
We are currently starting to deal with the technical aspects of our single-family home.
I haven’t found a thread discussing whether a ventilation system generally makes sense or not. So here is a general discussion thread on the topic:
At first, we looked into various timber frame construction providers, which made us quite sensitive in this area. Naturally, a ventilation system is quite important due to the tighter building envelope, which I can completely understand. However, everything is also marketed accordingly...
Since we have now decided to go with a regional solid construction company, completely different questions arise:
I currently have a detailed offer from a solid construction company:
- $10,000 additional cost for thermal insulation measures
- $13,000 additional cost for a central ventilation system or $9,000 additional cost for a decentralized ventilation system
--> So the repayment subsidy of $18,000 is of little use to me; on the contrary, I am even paying extra for this (of course, I get a “better” house in return).
Key Data:
- Single-family home city villa, 150m² (1,615 ft²) with basement
- Air-to-water heat pump
- Building material: brick
The questions I am now asking myself:
1. Is a ventilation system even necessary to achieve KfW 55 standard?
2. If yes, would it maybe make more sense to go for KfW 70 and forget about the subsidy?
3. Is a ventilation system really that great? There are many reports about noise, high maintenance, etc.
4. If yes, in our building project would a decentralized or central system be better? I have read a lot of positive things about decentralized systems, so central ones might not be an option? Is that correct or not?
5. Is it even possible to reach KfW 55 standard otherwise? Do you really have to ventilate every 2 hours? Are there any experiences?
6. Is the additional $10,000 cost for KfW 55 without a ventilation system justified? Are the prices for the ventilation systems justified?
I know this is an endless debate and there are clearly two opinions here. However, we find it really difficult to make a decision. Maybe a few discussions and information here will help us make up our minds.
Thank you for your responses.
@pagoni2020, I think I might have expressed myself somewhat unclearly. According to calculations, the house already meets the KfW-55 standard. =) I will inquire about it tomorrow.
@majuhenema, the main concern is the ventilation system... It is definitely interesting to hear your friends’ opinion.
However, the fact remains that the entire thread is clearly in favor of the ventilation system.
@pagoni2020, I think I might have expressed myself somewhat unclearly. According to calculations, the house already meets the KfW-55 standard. =) I will inquire about it tomorrow.
@majuhenema, the main concern is the ventilation system... It is definitely interesting to hear your friends’ opinion.
However, the fact remains that the entire thread is clearly in favor of the ventilation system.
M
majuhenema8 Apr 2021 21:19Hardi88 schrieb:
@majuhenema, the main focus is on the ventilation system... It’s definitely interesting to hear your friends’ opinions.That’s why I would have preferred to call or contact the general contractor sooner rather than later.
Hardi88 schrieb:
The fact is, however, that the entire thread clearly supports the ventilation system.Definitely. This forum is such a great help, and I’m grateful for so many threads and the personal advice.
Hardi88 schrieb:
After reading all the posts, I feel like I’m suffocating in a KfW55 house without controlled mechanical ventilation. :-D I have that feeling in nearly every house built to the Energy Saving Ordinance standards, but many are used to it and just think that’s how it is.
I am another voice in favor of controlled residential ventilation. We have been living in our newly built KFW55 house with a central ventilation system for half a year now.
We initially had the costs calculated individually – the price might not be very useful to you since our standard already included a decentralized ventilation system. The extra cost for the central system was between 5,000 and 6,000 euros.
In the end, we built with a combined unit (air-to-water heat pump, controlled residential ventilation, and hot water all in one large unit). I have never had air quality this good before; we love the controlled residential ventilation.
We initially had the costs calculated individually – the price might not be very useful to you since our standard already included a decentralized ventilation system. The extra cost for the central system was between 5,000 and 6,000 euros.
In the end, we built with a combined unit (air-to-water heat pump, controlled residential ventilation, and hot water all in one large unit). I have never had air quality this good before; we love the controlled residential ventilation.
So, I checked again.
With the general contractor (or rather their HVAC subcontractor, who dropped out because of my detailed questions about heating and ventilation), the additional cost would have been about 20,000 EUR (gross) (approximately 21,500 USD) (but that also includes adding another floor height in the upper floor to accommodate the ducts for the ground floor ventilation within the floor structure, which costs around 1,900 EUR (gross) (about 2,000 USD)).
I then found my own HVAC specialist, and the portion for the mechanical ventilation with heat recovery is about 8,400 EUR (gross) (around 9,000 USD), plus the increased floor height and extra insulation (about 500 EUR (gross) (approximately 540 USD)), and possibly a few core drillings.
So, in total nearly 12,000 EUR (gross) (around 12,800 USD). The system itself is a Vaillant RecovAir 260. The house has a living area of 162 m² (about 1,743 sq ft).
I estimate that an extra cost of 10,000–15,000 EUR (gross) (approximately 10,700–16,000 USD) for this through a general contractor would still be typical for you. More than that usually means the contractor isn’t really interested in such a job.
With the general contractor (or rather their HVAC subcontractor, who dropped out because of my detailed questions about heating and ventilation), the additional cost would have been about 20,000 EUR (gross) (approximately 21,500 USD) (but that also includes adding another floor height in the upper floor to accommodate the ducts for the ground floor ventilation within the floor structure, which costs around 1,900 EUR (gross) (about 2,000 USD)).
I then found my own HVAC specialist, and the portion for the mechanical ventilation with heat recovery is about 8,400 EUR (gross) (around 9,000 USD), plus the increased floor height and extra insulation (about 500 EUR (gross) (approximately 540 USD)), and possibly a few core drillings.
So, in total nearly 12,000 EUR (gross) (around 12,800 USD). The system itself is a Vaillant RecovAir 260. The house has a living area of 162 m² (about 1,743 sq ft).
I estimate that an extra cost of 10,000–15,000 EUR (gross) (approximately 10,700–16,000 USD) for this through a general contractor would still be typical for you. More than that usually means the contractor isn’t really interested in such a job.
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