We are planning a new build as an energy-efficient house according to the Energy Saving Ordinance, KfW70 standard. The developer claims that with very good insulation, solar thermal systems, and a condensing boiler, etc., this can be achieved without mechanical ventilation. A new build is sealed quite tightly as verified by a blower door test. The developer says we do not need to worry about moisture problems.
We are also used to regular manual ventilation from living in our old house... However, there the cold, fogged-up window was a reliable indicator...
The additional costs for a ventilation system would be significant...
What do the experts here think? Is it better not to forgo such a system, or does it not matter? I do not want to suffocate at night or discover mold after two years...
We are also used to regular manual ventilation from living in our old house... However, there the cold, fogged-up window was a reliable indicator...
The additional costs for a ventilation system would be significant...
What do the experts here think? Is it better not to forgo such a system, or does it not matter? I do not want to suffocate at night or discover mold after two years...
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Bulla20009 Sep 2010 08:19Sorry, but such complex sentences with multiple subordinate clauses and several parentheses do not necessarily improve understanding.
@Bauexperte: Could you please rewrite it more clearly? For example, we will have a single-layer exterior wall (T10, 36.5cm (14.4 inches) or T9, 36.5cm (14.4 inches)) and KfW70 standard. In addition, the new heating unit from AI (air heat pump, domestic hot water, and controlled residential ventilation).
@Bauexperte: Could you please rewrite it more clearly? For example, we will have a single-layer exterior wall (T10, 36.5cm (14.4 inches) or T9, 36.5cm (14.4 inches)) and KfW70 standard. In addition, the new heating unit from AI (air heat pump, domestic hot water, and controlled residential ventilation).
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Bauexperte9 Sep 2010 10:04Hello,
It is advisable if the house is equipped with external thermal insulation composite system (ETICS).
Kind regards
Mönschen schrieb:
So, as I understand from this, a house with a 30cm (12 inches) Ytong exterior wall and 6cm (2.5 inches) insulation (primary energy demand 60.2 kWh/m²/a) should have a ventilation system????
It is advisable if the house is equipped with external thermal insulation composite system (ETICS).
Kind regards
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Bauexperte9 Sep 2010 10:38Hello,
In simple terms: once a masonry wall with external thermal insulation composite system (ETICS) finished with synthetic resin plaster is constructed, a ventilation system is definitely recommended. Such a wall assembly is usually so airtight that without mechanical ventilation, the risk of mold growth would be too high.
With the wall construction you prefer, controlled mechanical ventilation is not absolutely necessary if you ventilate sufficiently; ignoring for the moment the costs and benefits of heat recovery. How much "sufficient" ventilation means will become clear once you have the results of the blower door test. A reference value: the more the permissible maximum air change rate – which is 3.0 air changes per hour (ACH) for homes relying on window ventilation – is undershot, the more necessary it is to regularly ventilate through the existing windows.
Best regards
Bulla2000 schrieb:
@Bauexperte: could you please explain it more clearly? For example, we will have a single-layer exterior masonry wall (T10, 36.5cm (14.4 inches) or T9, 36.5cm (14.4 inches)) and KfW70 standard. In addition, the new heating system from AI (air source heat pump, domestic hot water, and controlled mechanical ventilation with heat recovery).
In simple terms: once a masonry wall with external thermal insulation composite system (ETICS) finished with synthetic resin plaster is constructed, a ventilation system is definitely recommended. Such a wall assembly is usually so airtight that without mechanical ventilation, the risk of mold growth would be too high.
With the wall construction you prefer, controlled mechanical ventilation is not absolutely necessary if you ventilate sufficiently; ignoring for the moment the costs and benefits of heat recovery. How much "sufficient" ventilation means will become clear once you have the results of the blower door test. A reference value: the more the permissible maximum air change rate – which is 3.0 air changes per hour (ACH) for homes relying on window ventilation – is undershot, the more necessary it is to regularly ventilate through the existing windows.
Best regards
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