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.
T
T_im_Norden27 May 2020 11:19How can we tell you if it is affordable?
It only depends on what your supplier charges.
If it is the one who already wanted 29,000 for a heat pump, then probably not.
It only depends on what your supplier charges.
If it is the one who already wanted 29,000 for a heat pump, then probably not.
Tego12 schrieb:
To be honest, I have no idea since it was included in my fixed price from the start. I have a Zehnder Q350 myself, but the additional cost for the enthalpy heat exchanger was definitely under 1,000€ (about $1,100). T_im_Norden schrieb:
How should we tell you whether it’s possible price-wise?
That depends entirely on what your supplier charges.
If it’s the one who already wanted 29,000€ (about $32,000) for the heat pump, then probably not. Definitely. But I should also know what the reference prices generally are, so I can estimate whether I’m being overcharged or not.
The one who wanted 29k for the heat pump offered me KfW 55 standards with a central ventilation system for over 22,000€ (about $24,000) total.
T
T_im_Norden27 May 2020 13:10Reference prices are not really meaningful.
For example, if I pay 1000 euros for something in Schleswig-Holstein, it might cost 2500 euros in Bavaria.
Both prices can be expensive or reasonable.
For example, if I pay 1000 euros for something in Schleswig-Holstein, it might cost 2500 euros in Bavaria.
Both prices can be expensive or reasonable.
Why are you so focused on KfW 55 + controlled residential ventilation?
Just go for the energy saving regulation / KfW 70 with a proper controlled residential ventilation system with enthalpy recovery, and that’s it. Costs stay reasonable and the comfort gain is significant.
What I would rather plan for is a split air conditioning system for the bedrooms upstairs. In well-insulated houses, heat doesn’t escape easily once it’s inside. Unfortunately, I missed this and will therefore include a retrofit solution.
Just go for the energy saving regulation / KfW 70 with a proper controlled residential ventilation system with enthalpy recovery, and that’s it. Costs stay reasonable and the comfort gain is significant.
What I would rather plan for is a split air conditioning system for the bedrooms upstairs. In well-insulated houses, heat doesn’t escape easily once it’s inside. Unfortunately, I missed this and will therefore include a retrofit solution.
RFR schrieb:
Why are you so fixed on KfW 55 plus mechanical ventilation with heat recovery?
Just go for the Energy Saving Ordinance / KfW 70 standard with a proper mechanical ventilation system with enthalpy recovery, and that’s enough. The costs stay reasonable, and the comfort improvement is considerable.
What I would rather plan for is a split air conditioning system for the bedrooms on the upper floor. In well-insulated houses, heat doesn’t escape easily once it’s inside. Unfortunately, I overlooked this and will integrate a retrofit solution accordingly. KfW 70 with mechanical ventilation? Then I wouldn’t receive a repayment bonus of €18,000.
Even though quite a bit has already been said, I have to add my two cents as well.
A well-made photovoltaic system requires virtually no maintenance. You can clean the panels occasionally, but it’s not necessary.
Heat pumps should be serviced regularly.
For a ventilation system, filters need to be replaced or cleaned, and the ducts should be cleaned approximately every 10 years. That’s basically it.
Ventilation systems, heat pumps, etc., are no longer new but are absolutely state of the art for new builds!
The “plastic sheets” you mentioned are already outdated. Good timber house builders no longer use large plastic membranes but instead seal only the joints with adhesive tapes. Airtightness on surfaces is often achieved with OSB boards, solid wood, or similar materials.
If “plastic sheet” was meant as a synonym for “airtight,” that is also not new but long since standard practice and sensible.
Only many who don’t have one speak negatively about it.
And yes, you don’t have to have one, but it helps you reach a better energy standard (KFW), which comes with lower heating costs and a significant increase in comfort.
exto1791 schrieb:No one can give you an exact figure. But generally, the operating costs shouldn’t be higher than the heating cost savings you gain through heat recovery.
Can someone tell me roughly how high the running costs of a central ventilation system are?
exto1791 schrieb:Please inform yourself properly before spreading such nonsense!
Heat pump, ventilation system, and possibly photovoltaic? Three technical devices requiring a lot of maintenance..
A well-made photovoltaic system requires virtually no maintenance. You can clean the panels occasionally, but it’s not necessary.
Heat pumps should be serviced regularly.
For a ventilation system, filters need to be replaced or cleaned, and the ducts should be cleaned approximately every 10 years. That’s basically it.
exto1791 schrieb:Of course, that’s possible! But then you can forget about KFW funding, and in my opinion, it’s no longer state of the art.
I would like to do without all of that if possible.
exto1791 schrieb:Once again, it’s clear you don’t know what you’re talking about!
I have some concerns in this area… Maybe it’s because it’s still a “new thing” and is only gradually becoming a topic, due to the plastic sheets currently being used in construction.
Ventilation systems, heat pumps, etc., are no longer new but are absolutely state of the art for new builds!
The “plastic sheets” you mentioned are already outdated. Good timber house builders no longer use large plastic membranes but instead seal only the joints with adhesive tapes. Airtightness on surfaces is often achieved with OSB boards, solid wood, or similar materials.
If “plastic sheet” was meant as a synonym for “airtight,” that is also not new but long since standard practice and sensible.
exto1791 schrieb:That’s not true either. Almost everyone who has a ventilation system says they are very satisfied and would do it again.
I know… There are just so many different opinions on this topic, which makes it incredibly difficult.
Only many who don’t have one speak negatively about it.
And yes, you don’t have to have one, but it helps you reach a better energy standard (KFW), which comes with lower heating costs and a significant increase in comfort.
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