Our construction supervisor (BU) is very honest, and we, as well as others, trust him a lot.
However, he is not a fan of ventilation systems.
Here are the prices he quoted. Are there
1. Solutions that are more integrated into the wall or similar, to avoid additional height increases, and
2. Is the price reasonable?
Total area is 187 sqm (2013 sq ft), including about 40 sqm (430 sq ft) of an extension. The rest is spread over two levels in a town villa style.
There is a ceiling opening of about 9 sqm (97 sq ft) to the first floor, which is not included in the 187 sqm (2013 sq ft).
Attached is the text from the BU.
Pluggit Avent fresh air unit with heat recovery included.
Aluminum cross counterflow heat exchanger
Including air ducts, supply and exhaust air outlets, silencers, distributor, cover grilles in standard white plastic, supply and install 14,192.58 €
Blower door test mandatory when installing ventilation system 476.00 €
Increase of total floor construction height from 14 cm (5.5 inches) to 18 cm (7 inches) on the upper floor
By adding 3 cm (1.2 inches) more styrofoam insulation 2,988.97 €
Enthalpy exchanger and summer bypass
No costs yet
However, he is not a fan of ventilation systems.
Here are the prices he quoted. Are there
1. Solutions that are more integrated into the wall or similar, to avoid additional height increases, and
2. Is the price reasonable?
Total area is 187 sqm (2013 sq ft), including about 40 sqm (430 sq ft) of an extension. The rest is spread over two levels in a town villa style.
There is a ceiling opening of about 9 sqm (97 sq ft) to the first floor, which is not included in the 187 sqm (2013 sq ft).
Attached is the text from the BU.
Pluggit Avent fresh air unit with heat recovery included.
Aluminum cross counterflow heat exchanger
Including air ducts, supply and exhaust air outlets, silencers, distributor, cover grilles in standard white plastic, supply and install 14,192.58 €
Blower door test mandatory when installing ventilation system 476.00 €
Increase of total floor construction height from 14 cm (5.5 inches) to 18 cm (7 inches) on the upper floor
By adding 3 cm (1.2 inches) more styrofoam insulation 2,988.97 €
Enthalpy exchanger and summer bypass
No costs yet
M
mariano.dechow10 Dec 2023 10:14Our screed is also 18 cm (7 inches) thick.
Excerpt from the building specifications:
A cement screed is installed according to the manufacturer’s guidelines. The screed is suitable for underfloor heating systems. The total floor construction, including the final floor covering, measures 18 cm (7 inches) on the ground floor. Insulation boards, with thickness based on the thermal insulation certification, are fully installed beneath the underfloor heating system. The drying ventilation after screed installation is carried out by the client following the contractor’s instructions.
Well, his opinion is that a mechanical ventilation system with heat recovery is just a money-making scheme. He would install one, but he’s not a fan.
Excerpt from the building specifications:
A cement screed is installed according to the manufacturer’s guidelines. The screed is suitable for underfloor heating systems. The total floor construction, including the final floor covering, measures 18 cm (7 inches) on the ground floor. Insulation boards, with thickness based on the thermal insulation certification, are fully installed beneath the underfloor heating system. The drying ventilation after screed installation is carried out by the client following the contractor’s instructions.
Well, his opinion is that a mechanical ventilation system with heat recovery is just a money-making scheme. He would install one, but he’s not a fan.
C
Costruttrice10 Dec 2023 10:42mariano.dechow schrieb:
Well, his statement is that a mechanical ventilation system with heat recovery is just a way to make money. He would install it, but he's not a fan. Our general contractor said exactly the same thing during the construction of our first house, and the energy consultant(!) agreed with him. We decided against it at the time, later regretted it a lot, and ended up retrofitting decentralized units in some rooms. That was better than nothing, but it definitely could not compare to a central mechanical ventilation system with heat recovery.
For the second house, a central mechanical ventilation system with heat recovery was unquestionably the way to go for us. If that’s no longer financially feasible, then at least install a decentralized system.
mariano.dechow schrieb:
Is there no option without raising the floor, for example through the wall? The units need to be distributed in all rooms, which can only be done through the floor or ceiling.
In our case, they are installed in the ceiling, which was lowered with a suspended ceiling. But that was planned from the beginning.
R
Raiweired10 Dec 2023 10:44mariano.dechow schrieb:
Well, his statement is that a mechanical ventilation system for residential buildings is just a way to make money. He would install it himself but is not a fan.I agree with that. I have been living in a KfW55 house for 16 months and decided against both decentralized and centralized ventilation systems, and I have not regretted that decision so far. Ventilating once a day for a few minutes is enough. Even when we are on vacation for three weeks and no ventilation takes place, the humidity levels on the measuring devices I have placed in every room remain fine.
Raiweired schrieb:
Opening the windows for a few minutes once a day is enough. We'll see each other again in 5 years in the thread "Help, mold everywhere in the house and guests say they get headaches here."
Ventilating only once a day goes against all recognized guidelines for ventilation concepts in new buildings.
By the way, this is what the CO2 concentration looks like DESPITE controlled mechanical ventilation in a 60sqm (645 sq ft) open-plan room when 4 people are cooking and spending the evening together:
K
KarstenausNRW10 Dec 2023 11:21I agree in favor of mechanical ventilation with heat recovery. From my experience in my previous house with the decentralized system, and now again during renovation using a decentralized system, I stand by it: never again without it.
Yes, manual ventilation is possible. But it requires a) ventilating multiple times a day throughout the entire house, b) regardless of weather conditions, c) it doesn’t help with unpleasant odors in the bedroom at night, and d)...
However, without sufficient budget, it becomes difficult. In that case, the second-best option, decentralized mechanical ventilation with heat recovery, is still the perfect alternative (for example, installed in the window reveals). And if that is still not feasible, please at least use trickle vents in the window frame.
Anyone claiming how great a new building is without mechanical ventilation with heat recovery has not experienced a functioning system. Preventing mold is possible without such a system, but providing consistently fresh air (and ideally without pollen thanks to proper filters) is not achievable or at least cannot be done as effectively as with mechanical ventilation with heat recovery.
P.S. The price of €14,000 (excluding any increase from underfloor heating installation—which I don’t understand as necessarily required) is somewhat high. Either there is a prefabricated concrete ceiling—where the pipes can be installed alongside other components—or a cast-in-place ceiling—where pipes can also simply be laid. Depending on structural requirements, a bit more steel or concrete might be needed. The floor construction itself does not change. This shows that the general contractor simply didn’t want to deal with it.
Yes, manual ventilation is possible. But it requires a) ventilating multiple times a day throughout the entire house, b) regardless of weather conditions, c) it doesn’t help with unpleasant odors in the bedroom at night, and d)...
However, without sufficient budget, it becomes difficult. In that case, the second-best option, decentralized mechanical ventilation with heat recovery, is still the perfect alternative (for example, installed in the window reveals). And if that is still not feasible, please at least use trickle vents in the window frame.
Anyone claiming how great a new building is without mechanical ventilation with heat recovery has not experienced a functioning system. Preventing mold is possible without such a system, but providing consistently fresh air (and ideally without pollen thanks to proper filters) is not achievable or at least cannot be done as effectively as with mechanical ventilation with heat recovery.
P.S. The price of €14,000 (excluding any increase from underfloor heating installation—which I don’t understand as necessarily required) is somewhat high. Either there is a prefabricated concrete ceiling—where the pipes can be installed alongside other components—or a cast-in-place ceiling—where pipes can also simply be laid. Depending on structural requirements, a bit more steel or concrete might be needed. The floor construction itself does not change. This shows that the general contractor simply didn’t want to deal with it.
M
mariano.dechow10 Dec 2023 11:25I need to correct myself. When he says "3k tight," he is only referring to the ceiling, not the floor slab.
Floor Slabs
Reinforced concrete slabs made from precast filigree elements finished on the underside, with a topping concrete layer. Thickness and reinforcement according to structural engineering. The ceiling above the upper floor will be constructed as a timber collar beam ceiling.
The joints in the ceilings will be sealed with fiber-reinforced joint filler.
Floor Slabs
Reinforced concrete slabs made from precast filigree elements finished on the underside, with a topping concrete layer. Thickness and reinforcement according to structural engineering. The ceiling above the upper floor will be constructed as a timber collar beam ceiling.
The joints in the ceilings will be sealed with fiber-reinforced joint filler.
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