KFW40 House Project 2020 *Planning Ideas*

KfW55 is already quite good, especially with the new subsidy. I would only do better if it somehow works out and is only a little more expensive.

Controlled residential ventilation is better centralized.

Stay flexible in the early planning phase. I hardly think your heart is set on Ytong
Therefore, I wouldn’t commit to the wall and general structure so early, but make it dependent on the provider. There, you can possibly ask in detail and make adjustments if something doesn’t please you.

What would you prefer regarding the walls? Ytong was recommended to me by some friends and family.

Centralized controlled residential ventilation worries me because of the costs...

Ytong was recommended to me by some friends and family.

for an affordable house according to the Energy Saving Ordinance or for that matter KFW-70. Yes, gladly. Upgrading it to KfW-40 requires such contortions behind the scenes that you end up paying the cost advantage twice. Use a timber frame or sand-lime brick with ETICS. Wood fiber boards instead of polystyrene in the ETICS are becoming increasingly popular, not much more expensive and if the plasterer works carefully also durable for decades and afterwards very easy to dispose of.

for an affordable house according to the Energy Saving Ordinance or for that matter KfW-70. Yes, gladly. Upgrading that to KfW-40 requires such contortions in the background that you end up paying twice for the cost advantage. Use timber frame or sand-lime brick with ETICS.

Wood fiber boards instead of polystyrene in ETICS are becoming increasingly popular, not much more expensive, and if the plasterer works carefully, also durable for decades and afterwards very easy to dispose of.

Interesting alternatives, I will read up on that. To sum up: With Ytong I can probably achieve a maximum of KfW 55, going beyond that is extremely difficult. For
How about ventilation, are there advocates of decentralized systems here? The better the KfW standard, the more I suppose I would have to invest in ventilation as well.

What would you prefer regarding the walls? Ytong was recommended to me by some friends and family.

I would first stay open and listen to what and why is offered to meet the KfW standard at certain costs. It doesn’t make sense to choose a specific brick and then the preferred company doesn’t use it. The same goes for the foundation slab, etc., get offers, which can still be questioned later. Monolithic construction with good insulation is probably more expensive and more difficult. The material of the exterior walls is overrated. If no special sound insulation is required, then it doesn’t matter. There are more important things to plan in the house. Forgetting an important socket can sometimes make a bigger difference. I took what my architect recommended and what is common here: Ytong, mineral wool, clinker brick. Today I might choose sand-lime brick, but in my daily life it would make no difference. Ventilation is comfort and costs money. Decentralized ventilation in a single-family house is a compromise I would not make: noise, holes in the wall, exterior appearance, a dozen devices and sources of error,... Google the advantages and disadvantages of decentralized/centralized and decide for yourself. I wouldn’t install anything just because of a one-time subsidy if I am not convinced of it otherwise.

Ceiling insulation via Ytong ceiling (maybe too expensive!?)

What do you expect from it?

What do you expect from it?

I was under the impression that this would be better for kfw40 because in the building description of offer 1 a precast concrete slab was planned and in offer 2 a wooden ceiling with insulation wool. This seemed "insufficient" in terms of insulation. Maybe sufficient for kfw55, though? I really like the central ventilation by Zender from the videos available on YT. Both companies would like to build with 36.5 Ytong, by the way. However, so far they have only planned everything according to the Energy Saving Ordinance and not according to KfW. I will confront them with this.