Hello everyone,
maybe someone here can give us a good tip, as we are quite uncertain about a ventilation system.
We are planning to build a house (solid construction) according to KfW 70 standards, with underfloor heating, a fireplace, and a solar system. That much is already decided.
We received an offer from Company A for a ventilation system with heat recovery, and the salesperson recommended it to us.
At Company B, the ventilation system is significantly more expensive, and the salesperson told us that since the house is so well insulated, moisture would not be an issue... where would it come from? The rest could be regulated by normal airing anyway.
(I also think he realized that his ventilation system would have blown our budget and now I worry that he advised us against it just for that reason!)
My husband and I are laypersons, but my instinct tells me that the better the house is insulated, the more problems I would have getting rid of moisture and stale air inside the house, right?
After all, a blower door test does show that there is very little air circulation.
Am I completely wrong?
We are a bit torn now, since such a system is not exactly cheap! But is it necessary, or just a nice extra?
Thank you very much for your help!
maybe someone here can give us a good tip, as we are quite uncertain about a ventilation system.
We are planning to build a house (solid construction) according to KfW 70 standards, with underfloor heating, a fireplace, and a solar system. That much is already decided.
We received an offer from Company A for a ventilation system with heat recovery, and the salesperson recommended it to us.
At Company B, the ventilation system is significantly more expensive, and the salesperson told us that since the house is so well insulated, moisture would not be an issue... where would it come from? The rest could be regulated by normal airing anyway.
(I also think he realized that his ventilation system would have blown our budget and now I worry that he advised us against it just for that reason!)
My husband and I are laypersons, but my instinct tells me that the better the house is insulated, the more problems I would have getting rid of moisture and stale air inside the house, right?
After all, a blower door test does show that there is very little air circulation.
Am I completely wrong?
We are a bit torn now, since such a system is not exactly cheap! But is it necessary, or just a nice extra?
Thank you very much for your help!
Hello,
The importance and influence of the climate location as well as user behavior on the energy balance seem to be unknown to you. Otherwise, how could one come to such general statements for and against.
Best regards.
Bauexperte schrieb:What does this heating demand calculation look like?
...I am definitely capable of creating a heating demand calculation and ....
Bauexperte schrieb:I never claimed it was a "game changer"! More like the lesser evil.
In this context, also a cost-benefit analysis. Especially regarding the latter, heat recovery in a single-family house built to KfW 70 standard is not really effective—measured by the energy saved compared to the increased investment costs.
The importance and influence of the climate location as well as user behavior on the energy balance seem to be unknown to you. Otherwise, how could one come to such general statements for and against.
Best regards.
B
Bauexperte15 Feb 2011 09:36Hello €uro,
Unfortunately, your responses here in the forum often read differently.
You might be surprised – no, it is not unknown to me. However, I am happy to be convinced practically otherwise: in your opinion/experience, where does heat recovery ventilation (HRV), considering climate location and user behavior, really make sense in terms of cost versus benefit, especially for KfW 70 standard and below?
Kind regards
€uro schrieb:
I never claimed it was the "solution"! More like the lesser evil.
Unfortunately, your responses here in the forum often read differently.
€uro schrieb:
The importance and impact of the climate location as well as user behavior on the energy balance seem unknown to you.
You might be surprised – no, it is not unknown to me. However, I am happy to be convinced practically otherwise: in your opinion/experience, where does heat recovery ventilation (HRV), considering climate location and user behavior, really make sense in terms of cost versus benefit, especially for KfW 70 standard and below?
Kind regards
Hello,
It is not unusual that generalists disagree here, and for me, that is not really a problem.
Best regards
Bauexperte schrieb:I don’t think so. It just seems that everyone only wants to understand what fits their own perspective.
..Unfortunately, your replies here in the forum often read differently
Bauexperte schrieb:It is not my intention to convince anyone; I am simply expressing my opinion/view, as the forum cannot replace professional advice but only provide guidance. What each individual makes of it is up to them.
... However, I am happy to be convinced by practical experience to the contrary: ...
It is not unusual that generalists disagree here, and for me, that is not really a problem.
Best regards
Hello,
We are also planning a house with solid construction that must meet the KfW70 standard according to the development plan. House construction companies keep trying to convince us to install a ventilation system. We understand the companies’ economic interests.
However, we hope that with good insulation, a solar thermal system, and a large photovoltaic system (electricity generation) (southwest-facing roof, about 40cm (16 inches)²) enough renewable energy will be generated to meet KfW70. Does anyone have experience with this?
ARGUMENTS AGAINST the ventilation system include
- in addition to the well-known germ issues common with air conditioning systems,
- 1cm (0.4 inch) gaps under doors (which let noise travel everywhere),
- and above all, the uniform climate zone it creates in the house!
I definitely do not want that. I want to be able to have 24°C (75°F) in the bathroom during winter, 17°C (63°F) in the bedroom, 22°C (72°F) in the living room, and 15°C (59°F) in the pantry!
Because I don’t want to roast my food supplies at 24°C (75°F) or freeze in the bathroom at 17°C (63°F)!
I find the argument “Who would ventilate if no one is home?” strange. Where would all the moisture come from when no one is inside the house?
The uniform climate zone is the main reason I am against the ventilation system…
Has anyone already built a KfW70 house with a gas condensing boiler, insulation, solar thermal, and photovoltaics (WITHOUT ventilation and WITHOUT pumps)?
Best regards
We are also planning a house with solid construction that must meet the KfW70 standard according to the development plan. House construction companies keep trying to convince us to install a ventilation system. We understand the companies’ economic interests.
However, we hope that with good insulation, a solar thermal system, and a large photovoltaic system (electricity generation) (southwest-facing roof, about 40cm (16 inches)²) enough renewable energy will be generated to meet KfW70. Does anyone have experience with this?
ARGUMENTS AGAINST the ventilation system include
- in addition to the well-known germ issues common with air conditioning systems,
- 1cm (0.4 inch) gaps under doors (which let noise travel everywhere),
- and above all, the uniform climate zone it creates in the house!
I definitely do not want that. I want to be able to have 24°C (75°F) in the bathroom during winter, 17°C (63°F) in the bedroom, 22°C (72°F) in the living room, and 15°C (59°F) in the pantry!
Because I don’t want to roast my food supplies at 24°C (75°F) or freeze in the bathroom at 17°C (63°F)!
I find the argument “Who would ventilate if no one is home?” strange. Where would all the moisture come from when no one is inside the house?
The uniform climate zone is the main reason I am against the ventilation system…
Has anyone already built a KfW70 house with a gas condensing boiler, insulation, solar thermal, and photovoltaics (WITHOUT ventilation and WITHOUT pumps)?
Best regards
@DoaTJ:
I understand your reasoning.
Basically, it must be clear that a highly insulated house requires certain rules to be followed.
In my opinion, the most important thing is proper workmanship to prevent condensation caused by thermal bridges.
Furthermore, it is essential to ensure that the moisture generated inside the house is regularly removed by ventilating.
If someone is aware of this, it is quite possible to do without installing a central ventilation system, which—as you have already mentioned—also comes with some significant disadvantages.
Regards
I understand your reasoning.
Basically, it must be clear that a highly insulated house requires certain rules to be followed.
In my opinion, the most important thing is proper workmanship to prevent condensation caused by thermal bridges.
Furthermore, it is essential to ensure that the moisture generated inside the house is regularly removed by ventilating.
If someone is aware of this, it is quite possible to do without installing a central ventilation system, which—as you have already mentioned—also comes with some significant disadvantages.
Regards
P
Peppy19816 Feb 2013 09:00Hello,
we also want to build a solid construction house. Bungalow; 150 sqm (1,615 sq ft); attic not developed. We will have geothermal heating and NO ventilation system. The contract states that we are guaranteed a KfW 85 standard, and the final energy performance rating will only be determined after signing the contract. "But a KfW 70 is always achievable!" according to the seller. Is this common practice? Can you get KfW 70 without ventilation when using geothermal heating?
we also want to build a solid construction house. Bungalow; 150 sqm (1,615 sq ft); attic not developed. We will have geothermal heating and NO ventilation system. The contract states that we are guaranteed a KfW 85 standard, and the final energy performance rating will only be determined after signing the contract. "But a KfW 70 is always achievable!" according to the seller. Is this common practice? Can you get KfW 70 without ventilation when using geothermal heating?
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