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.
Mycraft schrieb:
Two systems running side by side like that are not always the best solution. Basically, I agree. But mechanical ventilation with heat recovery is fundamentally a rather simple system. What exactly is there to control extensively? I understand the bypass during heating, but why would I use the bypass in general when I need heating? That would only make sense in summer, when outside temperature < indoor temperature > target temperature.
What are the two systems supposed to do besides communicating with each other?
Tarnari schrieb:
35% of a maximum gross cost of 50,000 € (euros). Yes, it’s financially worthwhile, but technically? My general contractor still wants to install a combined system with a heat pump plus mechanical ventilation with heat recovery.
OWLer schrieb:
But controlled residential ventilation is basically a very "simple" system. It doesn’t have to stay simple. In fact, it usually isn’t. It’s just that the additional functions of the system beyond ventilation are often not documented.
Are you familiar with automatic climate control in cars during winter? Essentially the same principle.
OWLer schrieb:
My general contractor still wants to install a combined system with a heat pump plus controlled residential ventilation. Yes, some manufacturers combine these into one unit and consider it the ultimate solution.
OWLer schrieb:
Basically, I agree. But in principle, a mechanical ventilation system with heat recovery is a rather “simple” matter. What exactly is there to regulate? I understand the bypass during heating, but why would I use the bypass in general when I need to heat? I would only do that in summer when the outside temperature is lower than the indoor temperature and the setpoint temperature.
What are the two systems supposed to do except communicate with each other?
Yes, it’s financially worthwhile, but technically? My general contractor still wants to install a combined system with a heat pump plus mechanical ventilation with heat recovery. I can’t tell you. But we won’t apply for BAFA funding in connection with the mechanical ventilation with heat recovery. We will try to integrate as much KNX as possible.
We would have chosen the mechanical ventilation with heat recovery anyway, even without BAFA funding.
In general, we are going with the ground source heat pump, the mechanical ventilation with heat recovery, and KNX, even if there was no BAFA support.
That’s just a bonus for us.
I’m starting to feel like I live in the middle of nowhere on this topic. I have now spoken with five installation companies in the area and with a sales manager from Helios. None of them seem to be familiar with the BAFA subsidy program...... one even tried to tell me that the subsidy is only available for the renovation of old buildings.
I’m wondering how this topic can be so irrelevant when the subsidy amounts to several thousand euros!
I’m wondering how this topic can be so irrelevant when the subsidy amounts to several thousand euros!
Abzug86 schrieb:
I’m starting to feel like I’m living in the middle of nowhere when it comes to this topic. I have now called 5 installation companies in the area and even spoke with a sales manager from Helios. None of them seem to be familiar with the BAFA funding program...... one even tried to tell me that the funding only applies to renovations of older buildings.
I wonder how this topic can be so irrelevant when the funding amounts to several thousand euros?! That’s really disappointing.
We also contacted 2 heating and ventilation companies separately, and they were very knowledgeable. We will subcontract the entire process because the local construction companies are acting extremely clueless and have no interest in dealing with the whole matter.