ᐅ Energy-Efficient Renovation of Older Buildings – Is a Ventilation System Necessary or Not?
Created on: 4 Jan 2022 14:22
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Flitz86
Hello everyone,
we are planning to energetically upgrade a house built in 1978.
The goal is to achieve the KfW 85 standard (after consultation and calculations by the energy consultant).
Current situation:
Ground floor: 24cm (9.5 inches) expanded clay with 5cm (2 inches) internal insulation
Basement: 30cm (12 inches) concrete blocks
The exterior walls will be insulated with 10cm (4 inches) material with a thermal conductivity of 0.035 W/(m·K), and the ground floor with 10cm (4 inches) EPS insulation with a thermal conductivity of 0.032 W/(m·K).
The windows are already triple-glazed.
Additionally, a partial extension in timber frame construction will be added to meet the KfW 55 standard.
I have not yet discussed ventilation systems with my current carpenter and planner, with whom I want to carry out the project, as this topic has not come up so far. Since I am currently researching room climate and air conditioning (see: https://www.hausbau-forum.de/threads/Wärmepumpe-zur-raumkuehlung-in-kombination-mit-split-klimaanlage.42180/) and have contacted a company about this, they pointed out—independently of installing an air conditioning system—that I should definitely consider installing a ventilation system.
Does anyone have experience or recommendations on when a ventilation system is useful or even necessary, and when it is not?
What problems might I face if I decide against installing one?
I am generally inclined to prefer a decentralized ventilation system. This might even be retrofitted in the ground floor, which is not directly affected by the renovation (except for the insulation). I see a centralized ventilation system as very complex and demanding...
Best regards and thanks,
Christian
we are planning to energetically upgrade a house built in 1978.
The goal is to achieve the KfW 85 standard (after consultation and calculations by the energy consultant).
Current situation:
Ground floor: 24cm (9.5 inches) expanded clay with 5cm (2 inches) internal insulation
Basement: 30cm (12 inches) concrete blocks
The exterior walls will be insulated with 10cm (4 inches) material with a thermal conductivity of 0.035 W/(m·K), and the ground floor with 10cm (4 inches) EPS insulation with a thermal conductivity of 0.032 W/(m·K).
The windows are already triple-glazed.
Additionally, a partial extension in timber frame construction will be added to meet the KfW 55 standard.
I have not yet discussed ventilation systems with my current carpenter and planner, with whom I want to carry out the project, as this topic has not come up so far. Since I am currently researching room climate and air conditioning (see: https://www.hausbau-forum.de/threads/Wärmepumpe-zur-raumkuehlung-in-kombination-mit-split-klimaanlage.42180/) and have contacted a company about this, they pointed out—independently of installing an air conditioning system—that I should definitely consider installing a ventilation system.
Does anyone have experience or recommendations on when a ventilation system is useful or even necessary, and when it is not?
What problems might I face if I decide against installing one?
I am generally inclined to prefer a decentralized ventilation system. This might even be retrofitted in the ground floor, which is not directly affected by the renovation (except for the insulation). I see a centralized ventilation system as very complex and demanding...
Best regards and thanks,
Christian
Flitz86 schrieb:
What would be the specific advantage of a central ventilation system compared to a decentralized one?If the house has unused chimney flues, this is very advantageous:
It is common to supply fresh air to the main living areas and extract contaminated air on the same floor. For example, fresh air supply in the living room and exhaust air removed from the kitchen area. The air then flows across the floor. The exhaust air duct leads to a heat exchanger that preheats the incoming fresh air.
We sealed off 2 unused chimney flues at the top and installed only supply and exhaust air connections in the air shafts by drilling. This required only one additional fresh air intake opening to the outside, which also captures and utilizes heat loss from the heating system in the basement. This way, the basement is constantly ventilated and remains dry.
Of course, what is possible depends on the floor plan.
So here is a clear recommendation for a central system.
After about 3 months of operation, the air filters in the HVAC unit are black—meaning all the dust is kept out of the living spaces.
Flitz86 schrieb:
From my understanding as a non-expert, for a central ventilation system I would need to supply all rooms to be ventilated with ductwork. That seems rather difficult on the ground floor, especially since no structural changes are planned there.
In the upper floor, which is basically being renovated extensively, that would of course be feasible. And there actually is a chimney with a shaft that is no longer in use. You could install a central balanced ventilation system in the upper floor/attic and run the supply and exhaust ducts above the ceiling there, ventilating the ground floor through ceiling diffusers (i.e., from above). It depends on what you are doing and where you can find space and floor build-up height for it. This approach is accepted and often used in new constructions (for example, in our case 🙂.
Whatever you decide, make sure to consult a qualified planner.
B
Benutzer2004 Jan 2022 17:50Oh yes, if possible, I would also vote for a central system. BUT during a renovation, there is usually not enough space for the piping. That’s why I’m now living with a decentralized solution. It also works very well and quietly. In addition, it is significantly cheaper, and aside from electricity and core drilling, I didn’t need to carry out any other work. So the room height remained unchanged.
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motorradsilke4 Jan 2022 17:53Flitz86 schrieb:
Does anyone here have experience or recommendations on when a ventilation system is useful or even necessary, and when it is not?
What problems should I expect if I decide not to install one?
Regards and thanks
Christian None at all, you just have to ventilate yourself. The question is whether the comfort is worth it to you or if you prefer to ventilate manually anyway.
Thank you all for your feedback so far.
The trend seems to be leaning towards a ventilation system.
I think the best approach would be to get in touch with a specialized professional company.
As part of our renovation, the floor on the upper floor (OG) will be completely open, meaning that, in theory, ventilation openings could be installed through the ceiling on the ground floor (EG) (it is a timber beam ceiling between the ground floor and the upper floor).
However, I still can’t quite imagine how the ducts could be routed on the upper floor.
The floor construction must not be too thick, as the renovation and, for example, the stairs from the ground floor determine the height on the upper floor (the last step).
We also want to avoid lowering the ceiling too much – we really want to make the most of the room height here.
Regards,
Christian
The trend seems to be leaning towards a ventilation system.
I think the best approach would be to get in touch with a specialized professional company.
As part of our renovation, the floor on the upper floor (OG) will be completely open, meaning that, in theory, ventilation openings could be installed through the ceiling on the ground floor (EG) (it is a timber beam ceiling between the ground floor and the upper floor).
However, I still can’t quite imagine how the ducts could be routed on the upper floor.
The floor construction must not be too thick, as the renovation and, for example, the stairs from the ground floor determine the height on the upper floor (the last step).
We also want to avoid lowering the ceiling too much – we really want to make the most of the room height here.
Regards,
Christian
D
Deliverer20 Feb 2022 19:03So, how does it look? Is there already a strong breeze blowing?
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