Hi everyone,
We had a really exhausting day today.
We had two meetings at the prefabricated house center in Mannheim.
In the morning, we visited Keitel-Haus, and in the afternoon, Hanse Haus.
Our problem is: after meeting with Keitel-Haus, we thought we finally had clarity. But Hanse claims exactly the opposite.
At Keitel-Haus, this was our second long discussion, and this time we went into detail with a precise written quote and detailed descriptions of the individual building materials.
Now to the different statements, and we would appreciate your opinions as well.
You have the experience and are independent.
Exterior wall:
Keitel-Haus: vapor-permeable wall WITHOUT a vapor barrier (vapor retarder).
Including:
60mm (2.4 inches) wood fiber insulation board
200mm (7.9 inches) timber frame construction
200mm (7.9 inches) mineral fiber insulation
Wall thickness 29.2cm (11.5 inches)
Hanse: vapor-permeable wall WITH vapor retarder
Including:
150mm (5.9 inches) thermal insulation, thermal conductivity class 032
8mm (0.3 inches) OSB board
125mm (4.9 inches) timber frame construction (with mineral insulation)
8mm (0.3 inches) OSB board
vapor-permeable vapor retarder fleece
12.5mm (0.5 inches) gypsum board
So,
Keitel-Haus says: We build a proper vapor-permeable wall, so without any vapor retarders. This allows moisture to really escape outside, preventing mold growth.
Hanse says: That’s nonsense, there are no houses that can "breathe". We have a vapor retarder because we want to hold back water vapor, i.e., moisture. We don’t want it to enter the wall, as it would cause damage. Without a barrier, mold would eventually develop.
What is correct here?
Topic 2
Heating technology / ventilation:
Keitel-Haus:
They considered our wishes and said that while they think controlled residential ventilation is good, they do not recommend controlled ventilation with heat recovery. I don’t remember exactly why, but there was a lengthy explanation. Anyway, probably because of underfloor heating, we wanted a heat pump.
Hanse:
They tried to persuade us to get a different kind of heat pump and insisted it would be better to have controlled ventilation WITH heat recovery.
It would save energy, and windows can still be opened (which we want, especially at night while sleeping and sometimes in summer).
If I remember correctly, I recently read only negative things about that kind of heat pump, and that it would financially disadvantage us.
Hanse says: Nonsense. If the house is built properly and the system is installed correctly, this kind of heat pump is best, and they can ensure it is the most cost-effective.
Topic 3
KfW 40/55 standards
Keitel-Haus:
KfW 55 is optimal and can be achieved without problems according to our requirements (photovoltaics, underfloor heating, heat pump, vapor-permeable wall).
KfW 40 requires too much effort and is much too expensive. The savings wouldn’t justify it.
Hanse:
KfW 40 or better yet Passive House, since from 2020 Passive House standard is mandatory anyway.
The difference from KfW 55 to KfW 40 would only be about €9000 and corresponds to additional insulation under the slab and roof. No extra technology would be needed, and the savings would be enormous!
Their walls already meet KfW 40 as standard.
Topic 4:
Exterior wall insulation
Keitel-Haus builds with wood fiber insulation board. Styrofoam (EPS) is standard but not recommended because it is vapor-tight. That’s why they offer a better "open" wall.
I know Styrofoam is extremely poor in fire performance. I don’t like it at all.
Hanse:
I had no clear answer; I couldn’t really get details. They just said Styrofoam is not so bad, and their thermal insulation contains some graphite.
It seemed to me like Styrofoam with graphite additives or something similar.
I know, lots of questions again.
I have already spent many hours reading but still don’t feel much wiser.
These topics are very complex and sometimes a bit beyond me.
From the feeling we have, we would build with Keitel-Haus.
The Hanse representative was arrogant and "aggressive." I even almost argued with him because he was unwilling to discuss most points, including providing a written offer. He said he only bothers if he knows you really want to build with them. For me, a comparison makes no sense without different offers and service descriptions to compare.
We also looked at Fingerhut, but after 6 weeks they still haven’t provided an offer. So that’s a no-go for us. The "salesperson" seems to prefer working his side job (entertainer).
Rensch-Haus gave us many verbal promises that everything would be possible (of course, for extra money, everything is possible), but 90% of what should have been standard was not in the service description.
We had a really exhausting day today.
We had two meetings at the prefabricated house center in Mannheim.
In the morning, we visited Keitel-Haus, and in the afternoon, Hanse Haus.
Our problem is: after meeting with Keitel-Haus, we thought we finally had clarity. But Hanse claims exactly the opposite.
At Keitel-Haus, this was our second long discussion, and this time we went into detail with a precise written quote and detailed descriptions of the individual building materials.
Now to the different statements, and we would appreciate your opinions as well.
You have the experience and are independent.
Exterior wall:
Keitel-Haus: vapor-permeable wall WITHOUT a vapor barrier (vapor retarder).
Including:
60mm (2.4 inches) wood fiber insulation board
200mm (7.9 inches) timber frame construction
200mm (7.9 inches) mineral fiber insulation
Wall thickness 29.2cm (11.5 inches)
Hanse: vapor-permeable wall WITH vapor retarder
Including:
150mm (5.9 inches) thermal insulation, thermal conductivity class 032
8mm (0.3 inches) OSB board
125mm (4.9 inches) timber frame construction (with mineral insulation)
8mm (0.3 inches) OSB board
vapor-permeable vapor retarder fleece
12.5mm (0.5 inches) gypsum board
So,
Keitel-Haus says: We build a proper vapor-permeable wall, so without any vapor retarders. This allows moisture to really escape outside, preventing mold growth.
Hanse says: That’s nonsense, there are no houses that can "breathe". We have a vapor retarder because we want to hold back water vapor, i.e., moisture. We don’t want it to enter the wall, as it would cause damage. Without a barrier, mold would eventually develop.
What is correct here?
Topic 2
Heating technology / ventilation:
Keitel-Haus:
They considered our wishes and said that while they think controlled residential ventilation is good, they do not recommend controlled ventilation with heat recovery. I don’t remember exactly why, but there was a lengthy explanation. Anyway, probably because of underfloor heating, we wanted a heat pump.
Hanse:
They tried to persuade us to get a different kind of heat pump and insisted it would be better to have controlled ventilation WITH heat recovery.
It would save energy, and windows can still be opened (which we want, especially at night while sleeping and sometimes in summer).
If I remember correctly, I recently read only negative things about that kind of heat pump, and that it would financially disadvantage us.
Hanse says: Nonsense. If the house is built properly and the system is installed correctly, this kind of heat pump is best, and they can ensure it is the most cost-effective.
Topic 3
KfW 40/55 standards
Keitel-Haus:
KfW 55 is optimal and can be achieved without problems according to our requirements (photovoltaics, underfloor heating, heat pump, vapor-permeable wall).
KfW 40 requires too much effort and is much too expensive. The savings wouldn’t justify it.
Hanse:
KfW 40 or better yet Passive House, since from 2020 Passive House standard is mandatory anyway.
The difference from KfW 55 to KfW 40 would only be about €9000 and corresponds to additional insulation under the slab and roof. No extra technology would be needed, and the savings would be enormous!
Their walls already meet KfW 40 as standard.
Topic 4:
Exterior wall insulation
Keitel-Haus builds with wood fiber insulation board. Styrofoam (EPS) is standard but not recommended because it is vapor-tight. That’s why they offer a better "open" wall.
I know Styrofoam is extremely poor in fire performance. I don’t like it at all.
Hanse:
I had no clear answer; I couldn’t really get details. They just said Styrofoam is not so bad, and their thermal insulation contains some graphite.
It seemed to me like Styrofoam with graphite additives or something similar.
I know, lots of questions again.
I have already spent many hours reading but still don’t feel much wiser.
These topics are very complex and sometimes a bit beyond me.
From the feeling we have, we would build with Keitel-Haus.
The Hanse representative was arrogant and "aggressive." I even almost argued with him because he was unwilling to discuss most points, including providing a written offer. He said he only bothers if he knows you really want to build with them. For me, a comparison makes no sense without different offers and service descriptions to compare.
We also looked at Fingerhut, but after 6 weeks they still haven’t provided an offer. So that’s a no-go for us. The "salesperson" seems to prefer working his side job (entertainer).
Rensch-Haus gave us many verbal promises that everything would be possible (of course, for extra money, everything is possible), but 90% of what should have been standard was not in the service description.
305er schrieb:
What’s the financial difference between 70 and 55? Good question, but we want to be independent from electricity and gas, which is why we opted for a heat pump and a photovoltaic system. This way, you already achieve KFW 55 if the masonry and so on are suitable.
I refer here to my post #34 in the thread https://www.hausbau-forum.de/threads/solar-pv-wirtschaftlicher-Gesichtspunkt.13659/page-6.
During the time when you need your heating the most, your photovoltaic system produces the least.
EveundGerd19 Nov 2015 15:28Monolithic construction means building stone upon stone, which is commonly referred to as a solid or masonry house.
Your house probably won’t be completely independent of electricity and gas in the next few years, unless you already have a plan for heating and hot water production.
A micro combined heat and power (micro-CHP) unit might be suitable for this. It has an efficiency of nearly 90%, but it must be operated with gas. The investment cost is between 15,000 and 25,000 euros.
However, calculations often use older houses with high gas consumption as examples. It is questionable whether this investment is worthwhile for a new build.
I recommend purchasing expert knowledge in the form of a certified surveyor or building consultant. You will definitely need one during the house construction process, and they can already advise you now on the choice of builder, wall structure, and other details.
It is worthwhile to calculate the costs between KfW 70 and 55 energy standards. Also, calculate the additional investment plus interest costs! The difference may be so large that you won’t be able to recover this investment through heating savings during your lifetime.
Your house probably won’t be completely independent of electricity and gas in the next few years, unless you already have a plan for heating and hot water production.
A micro combined heat and power (micro-CHP) unit might be suitable for this. It has an efficiency of nearly 90%, but it must be operated with gas. The investment cost is between 15,000 and 25,000 euros.
However, calculations often use older houses with high gas consumption as examples. It is questionable whether this investment is worthwhile for a new build.
I recommend purchasing expert knowledge in the form of a certified surveyor or building consultant. You will definitely need one during the house construction process, and they can already advise you now on the choice of builder, wall structure, and other details.
It is worthwhile to calculate the costs between KfW 70 and 55 energy standards. Also, calculate the additional investment plus interest costs! The difference may be so large that you won’t be able to recover this investment through heating savings during your lifetime.
Uwe82 schrieb:
If you have a lot of time and want to get a real muscle ache, yes . We faced this issue ourselves and could have saved about €5000, as the materials would have been delivered. But those €5000 were definitely worth it to me. It’s worth mentioning that we used 15mm (0.6 inch) Fermacell boards. In large formats, one person alone can’t lift them.
Conclusion: You need at least two people working on it, and even then it’s hard physical work. If you’ve never done this before, you should stay away unless you have plenty of time and a lot of help. I agree with that. Especially when working on ceilings, you can quickly reach your limits. A drywall panel measuring 2.50 x 1.25 x 1.00 meters (8.2 x 4.1 x 3.3 feet) already has a considerable weight. You need to lift the panel up to the ceiling and hold it in place until it is properly screwed in. For this, you need at least two extra people or some kind of lifting device that can raise the panel to the ceiling and press it into place (this was discussed here some time ago).
It might be different with ceiling panels, though. These are manageable enough for DIY installation. If you like them. My parents have them in their attic. We didn’t want them.
First of all, sorry, I think I misunderstood something regarding the expert assessment.
So you mean I should look for an expert and go with them to the home builder or put the documents in front of them?
Independent of electricity and gas, I meant:
A photovoltaic system on the roof that feeds electricity to the heat pump, which then heats the hot water.
So I don’t need gas at all, and electricity only when it’s dark and the photovoltaic system is not producing.
What about ice storage? Cost/benefit?
Regarding photovoltaics, is it not worth it? Has anyone else had the same experience?
Doesn’t it also depend on where you live in Germany?
Today I only got a chance to call a local supplier about solid construction, who said I first need to find an architect who will prepare a tender, so I can then hire the company and they can tell me what it will cost.
But if I ask a few companies, will it already cost me several hundred euros just for the information?
So you mean I should look for an expert and go with them to the home builder or put the documents in front of them?
Independent of electricity and gas, I meant:
A photovoltaic system on the roof that feeds electricity to the heat pump, which then heats the hot water.
So I don’t need gas at all, and electricity only when it’s dark and the photovoltaic system is not producing.
What about ice storage? Cost/benefit?
Regarding photovoltaics, is it not worth it? Has anyone else had the same experience?
Doesn’t it also depend on where you live in Germany?
Today I only got a chance to call a local supplier about solid construction, who said I first need to find an architect who will prepare a tender, so I can then hire the company and they can tell me what it will cost.
But if I ask a few companies, will it already cost me several hundred euros just for the information?
305er schrieb:
Regarding photovoltaic systems, it’s not worth it—have others had the same experience?
Doesn’t it also depend on where you live in Germany? I didn’t say that—please read the entire linked thread. I am actually in favor of photovoltaic systems; I didn’t choose them without reason. However, I’ve noticed that the winter months produce much lower yields (almost no output) than expected.
It is a misconception that during late autumn, winter, and early spring, photovoltaics can largely power your heat pump. This does not work.
Yes, it partly depends on where you live. However, within Germany this is not the decisive factor. I would say there is at most a 5% difference in yield.
Regional differences become significant when comparing places like northern Norway and Italy.
By the way: we live in the Saar/Mosel region. Snow during winter is rather rare here, and we often have more sun than in other parts of Germany (except for the Föhn region). But last week or even the entire January, this regional advantage was basically irrelevant.
Hello,
once again regarding the wall construction.
What I find missing in both variants, and what would be a deal breaker for me, is an installation cavity.
Also, in timber frame construction, I would separate thermal insulation and weather protection with an air gap.
Our wall structure from inside to outside, for example, looks like this:
- Gypsum board 12.5 mm (0.5 inch)
- OSB 18 mm (0.7 inch)
- Installation cavity with 60 mm (2.4 inches) mineral wool
- OSB 18 mm (0.7 inch)
- Stud frame filled with 240 mm (9.4 inches) mineral wool
- Wood fiberboard 60 mm (2.4 inches)
- Counter battens / ventilation gap 40 mm (1.6 inches)
- Exterior cladding: FunderMax, Trespa, or Rockpanel
Olli
once again regarding the wall construction.
What I find missing in both variants, and what would be a deal breaker for me, is an installation cavity.
Also, in timber frame construction, I would separate thermal insulation and weather protection with an air gap.
Our wall structure from inside to outside, for example, looks like this:
- Gypsum board 12.5 mm (0.5 inch)
- OSB 18 mm (0.7 inch)
- Installation cavity with 60 mm (2.4 inches) mineral wool
- OSB 18 mm (0.7 inch)
- Stud frame filled with 240 mm (9.4 inches) mineral wool
- Wood fiberboard 60 mm (2.4 inches)
- Counter battens / ventilation gap 40 mm (1.6 inches)
- Exterior cladding: FunderMax, Trespa, or Rockpanel
Olli
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