ᐅ KFW 40 (Energy Saving Regulation 2014) without Ventilation – Retrofit Options

Created on: 17 Jan 2017 17:36
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Donut009
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Donut009
17 Jan 2017 17:36
Hello everyone,

First of all – I have researched the topic extensively and am familiar with the pros and cons. I’m not looking for a basic debate (I’m sure I’ve already read about 40 pages on this forum about that).

Facts:
1. We are very interested in a property offered by the developer as follows: built to KfW Efficiency House 70 standard (according to the 2014 Energy Saving Ordinance).
2. No ventilation system.
3. Construction is already well advanced (currently the underfloor heating is being installed).

Questions:
1. I always thought KfW 70 and the 2014 Energy Saving Ordinance were two different standards? Isn’t KfW 70 now aligned with the 2016 Energy Saving Ordinance? Or am I misunderstanding something?
2. If I were planning new construction, I would probably install a ventilation system. Since there are pros and cons, it seems to me that not having one is not a dealbreaker, but requires more caution and effort. Is there anything I should definitely ask about on this basis (ventilation concept, air exchange rate, etc.)? Does anything have to be specifically calculated and designed, or does the architect do that to the best of their knowledge and judgment?
3. Since construction is so far along, I can no longer retrofit mechanical ventilation. If I do encounter problems later on, what options do I have without having to dismantle the entire (new) house? I understand that this will cost several thousand euros.

Best regards,
Marco
Mycraft17 Jan 2017 18:42
1. As far as I know, KfW 70 no longer exists (but I could be wrong).

2. You would need to inquire about and adhere to the ventilation intervals.

3. You can install a decentralized system at any time, even now... it’s best to have the cables for it installed in the walls already.
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Donut009
17 Jan 2017 19:43
1. I believe construction started just before April 2016 (it’s almost finished now), which is why it is still listed as KfW 70. Otherwise, I agree with you.

2. Okay, I will do that. Does this mean a calculation is required?

3. The exterior of the house is already painted, and the underfloor heating is being installed inside. I’m afraid it’s too late now to add anything into the walls, right?
Mycraft17 Jan 2017 20:21
Whether it is still possible to install cables depends entirely on the construction method and the sequence of trades involved...