Hello,
even though similar questions have been asked here before, I am starting a new thread.
We are planning a new build and are currently comparing insulation options for the exterior walls, basement, roof, etc.
We want to build a solid structure with a double-shell masonry made of aerated concrete.
The construction companies all insulate the exterior walls with mineral wool at a thickness between 8 to 14 cm (3 to 6 inches), thermal conductivity value (WLG) 035.
For roof insulation, there is always a 20-24 cm (8 to 10 inches) insulation layer between the rafters with WLG 035. The attic space is insulated only if a finish is planned. If financially feasible, we would like to have this insulated as well.
Now the first question: can you recommend mineral wool insulation? And if yes, what thickness should be used and should one demand WLG 032 instead? Of course, better insulation is better, but what really makes sense when comparing initial investment costs to possible heating savings?
We also consulted a structural engineer who individually plans and supervises house constructions. He became quite concerned when looking at the specifications from the building companies. He recommends insulation with polyurethane boards having a thermal conductivity value (WLS) of 024 and a thickness of 20-24 cm (8 to 10 inches). For the roof, he recommends a full inboard insulation (above-rafter insulation) using the same material.
With this, our exterior wall would achieve a U-value of around 0.10-0.12 instead of possibly 0.16-0.18 with good mineral wool insulation (according to the information brochure).
Of course, this would be better, but his cost estimate showed that such a house would cost at least 50,000 € more and thus would no longer be financially feasible for us.
We really want to think this through carefully and do everything as properly and sensibly as possible and would be very grateful for professional answers!
Maya
even though similar questions have been asked here before, I am starting a new thread.
We are planning a new build and are currently comparing insulation options for the exterior walls, basement, roof, etc.
We want to build a solid structure with a double-shell masonry made of aerated concrete.
The construction companies all insulate the exterior walls with mineral wool at a thickness between 8 to 14 cm (3 to 6 inches), thermal conductivity value (WLG) 035.
For roof insulation, there is always a 20-24 cm (8 to 10 inches) insulation layer between the rafters with WLG 035. The attic space is insulated only if a finish is planned. If financially feasible, we would like to have this insulated as well.
Now the first question: can you recommend mineral wool insulation? And if yes, what thickness should be used and should one demand WLG 032 instead? Of course, better insulation is better, but what really makes sense when comparing initial investment costs to possible heating savings?
We also consulted a structural engineer who individually plans and supervises house constructions. He became quite concerned when looking at the specifications from the building companies. He recommends insulation with polyurethane boards having a thermal conductivity value (WLS) of 024 and a thickness of 20-24 cm (8 to 10 inches). For the roof, he recommends a full inboard insulation (above-rafter insulation) using the same material.
With this, our exterior wall would achieve a U-value of around 0.10-0.12 instead of possibly 0.16-0.18 with good mineral wool insulation (according to the information brochure).
Of course, this would be better, but his cost estimate showed that such a house would cost at least 50,000 € more and thus would no longer be financially feasible for us.
We really want to think this through carefully and do everything as properly and sensibly as possible and would be very grateful for professional answers!
Maya
Hello,
As the building expert already mentioned, you can also consider an air-source heat pump, provided the conditions are suitable.
This might even allow reaching KfW 55 standards, making solar panels unnecessary, effectively saving twice!
Best regards.
Maya2011 schrieb:
...No, actually a KfW 70 house, since we want a gas heating system, but with a SENSIBLE, possibly better insulation – without going overboard.
As the building expert already mentioned, you can also consider an air-source heat pump, provided the conditions are suitable.
This might even allow reaching KfW 55 standards, making solar panels unnecessary, effectively saving twice!
Best regards.
Hello,
We definitely do not want a heat pump here in the North.
I am more inclined to consider a combined heat and power plant...
So far, I have not been fully convinced by the way passive houses work. Usually, they still require an additional heating system.
However, I have read about passive houses that also use solar panels and have a gas heating system...
That could be a direction to consider.
We definitely do not want a heat pump here in the North.
I am more inclined to consider a combined heat and power plant...
So far, I have not been fully convinced by the way passive houses work. Usually, they still require an additional heating system.
However, I have read about passive houses that also use solar panels and have a gas heating system...
That could be a direction to consider.
Hello,
Best regards.
Maya2011 schrieb:A combined heat and power unit is usually not economically viable for a standard single-family or two-family house. The problem is the unused heat outside the heating season. Just have an energy balance calculation done.
...Then I am more likely to consider a combined heat and power unit...
Best regards.
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