Build according to KFW 70 or the Energy Saving Ordinance 2014

Can you take a look at the draft, see the link above. Please evaluate the floor plan to see what could be changed. What we don't like. Upstairs bathroom too small, storage room is nice, but somehow not nicely integrated

- thanks for the feedback and the positive response. So the whole thing was calculated at about 330 t, we would like to get down to 300 t. It always gets more expensive than planned anyway. We will also contribute our own work, but that does not amount to 30 t €, because material still has to be bought. Our architect now said that one could simply do without a ventilation system, which would be around 10 t €, but I would rather not. Additionally, building according to the 2014 Energy Saving Ordinance instead of KFW 70, although I don't even know how big the difference actually is. Are we talking about 10 t € plus the ventilation system or just 3000 - 4000 t €?! The idea of having the general contractor calculate against it is a good one. I just don't know if they would agree to such a split-level house. But sure, asking costs nothing. So far, we had thought to take over all service phases from the architect. Especially construction supervision is very important. That's the plan so far...

- glad to hear that the cost estimate might be roughly correct (the outdoor storage room and carport are not included). That reassures me a bit, so it won't be a complete crash landing later. We like the floor plan, only the upper floor not. The bathroom is too small for us; the question is how to change it without enlarging the building structure again and causing additional costs.

You are still in the planning phase, but already completely fixed on the overall shape and dimensions of the house body...

Yes, we really like the building structure, that’s true, but the problem is things like the upper floor which we don’t like at all. Honestly, I don’t see any solutions at the moment to change the upper floor so that it fits. That means a bigger bathroom with 2 children’s rooms and a master bedroom. We could enlarge the building structure, but that costs money again, and we are already close to the limit.

@@kbt09, @@BeHaElJa, @@Panama17 and I have already suggested quite a few things. But if you want to make progress, you have to have an approach, whether the proposals have reached you, meaning whether they find resonance or represent a no-go.
You also have to take your share in the discussion.

Another suggestion: 2 utility rooms, one on the ground floor for technology and storage, the second upstairs as a utility room.
Sizes adjusted so that instead of an office downstairs there is a bedroom, and upstairs the smaller office.

Cost-saving measures: eliminate the reading nook and gallery!

We didn’t really want the master bedroom downstairs and had dismissed the idea. It’s nice for later, but when the children are still small, we don’t find it so nice. I will still keep it as a possibility in the back of my mind.
We planned storage in the kitchen, but I am still not entirely happy with that.

Regarding the cost-saving measures:
We have almost already said goodbye to the reading nook. That would now be the first approach to saving costs.

First of all, a really very beautiful house! Basically, it can be said that the KFW efficiency house status (i.e. 40, 55, 70, 100, etc.) depends on the primary energy factor (i.e. final energy multiplied by an ecological factor for the type of your heating fuel) and the heat loss of your house compared to the reference building. You currently receive a loan of up to €50,000 per housing unit for the KFW 70 house at an interest rate of 0.85%; this is at least 1% below a normal construction financing concluded through the bank; KFW 100 house is no longer eligible for subsidies in new buildings. If you really want to save costs but still want to achieve KFW 70, I recommend installing a pellet condensing boiler with at least a 30 l/kW buffer storage instead of a gas boiler (primary energy factor 1.1) with solar support (which is positively credited in the energy saving ordinance verification). This is currently subsidized in new buildings with €3,500, so it is overall cheaper than the gas condensing boiler with solar support (disadvantage: increased space requirement for storage). At the same time, you have a primary energy factor of only 0.2 and, if desired and the transmission heat loss is not more than 85% compared to the reference building, you can save massively on thermal insulation (floor, roof, windows, facade). The overall higher energy costs must, of course, be weighed against the saved investment costs. What type of insulation is planned, standard ones like EPS, XPS, and mineral wool, or innovative ones like aerogel and vacuum insulation panels?