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.
exto1791 schrieb:
What would still be interesting is, if I build to KfW 70 standard, is a ventilation system then completely unnecessary? Would that really be a disadvantage? Just for my understanding. Is that still common practice nowadays? You can find the answers in my post!
It doesn’t make any difference whether you build to 70, 55, or 40, the houses are airtight!
That means either a ventilation system or appropriate manual ventilation.
I would even argue that with KfW 70 or the Energy Saving Ordinance, you might actually face mold problems sooner because the exterior wall will be correspondingly thinner, making the temperature on the interior side possibly lower and more prone to condensation than with the better insulated KfW 55 wall.
You also need to understand that the KFW “standards” are essentially well-calculated estimates. Depending on how you build, for example, just to comply with the energy saving regulations, you might find upon recalculating that, actually, you meet the requirements for KFW 55.
A bit of insulation at the floor slab here, some at the roof there, decent windows, and suddenly you may realize you have achieved KFW 55 without even intending to.
KFW is just smart calculation.
For KFW 55, you certainly don’t need an exceptionally well-insulated wall.
A bit of insulation at the floor slab here, some at the roof there, decent windows, and suddenly you may realize you have achieved KFW 55 without even intending to.
KFW is just smart calculation.
For KFW 55, you certainly don’t need an exceptionally well-insulated wall.
exto1791 schrieb:
- $10,000 surcharge for thermal insulation measuresI would really like to know what kind of "thermal insulation measures" these are. Hopefully, no one plans to simply stick insulation boards onto the bricks. There are definitely much better ways to do this, as Tarnari correctly pointed out:Tarnari schrieb:
For KFW 55, you certainly don’t need a specially insulated wall.
exto1791 schrieb:
did not find any thread on thisTry searching for Controlled Residential Ventilation, which is the abbreviation for controlled residential ventilation.Can anyone tell me approximately how high the ongoing costs of a central ventilation system are?
For me, due to the KfW55 subsidy, this is the only uncertain cost factor.
Heat pump, ventilation system, and possibly photovoltaic system? Three technical devices that require regular maintenance... I would prefer to avoid all of them if possible.
I’m just curious about the approximate annual costs for such a central ventilation system.
For me, due to the KfW55 subsidy, this is the only uncertain cost factor.
Heat pump, ventilation system, and possibly photovoltaic system? Three technical devices that require regular maintenance... I would prefer to avoid all of them if possible.
I’m just curious about the approximate annual costs for such a central ventilation system.
Similar topics