Single-family house, Energy Saving Ordinance 2016, developer recommends additional insulation - is it sensible?

Phew, the statement about aerated concrete and Poroton really hurts me. Such a general statement completely misses the point.
You have to achieve a certain "energy efficiency" with your entire house. That has nothing to do with the external wall or insulation individually.

Basically, you are of course completely right about that. The overall balance is important. If one position is "weak," the other positions have to compensate. However, I dare to doubt whether the necessary compensatory measures in my example (36.5 cm aerated concrete monolithic) are still economically sensible overall.

Are you aware of how much extra cost you have to meet the Energy Saving Ordinance with a gas boiler?

Yes, pretty much exactly 9,500,-. Didn’t you read my previous post? And with my post, I asked whether the 4,200 for additional insulation might possibly amortize itself, so that the gas boiler only has to make 4,300,- (consideration period 10 years).

You get into the Energy Saving Ordinance much easier with a heat pump with significantly less insulation hysteria that costs you a lot of money.

Uh, yes??? I had already written that as well.

Could it be that your "advisor" is interested in selling you something?

I don’t have an advisor, just a salesman—and he wants to sell me a house. Whether with gas or air-water heat pump doesn’t matter to him at all. And whether the air-water heat pump ends up with an annual performance factor of 1.5 also doesn’t...

My arguments for air-water heat pump:
Investment costs within range (presumably gas is cheaper)

No, it isn’t—see above. Would you like to also answer my question?

I think the chimney for gas is really not particularly relevant in the living space calculation.

In a standard single-family house, it often runs together with all other water pipes on the inside of the utility room upwards, so absolutely no loss of space...

The gas connection would have eaten up the additional costs for the air-water heat pump for us. Therefore, it was not even a question for us what kind of heating system we would choose. Moreover, with gas, a solar system for water would have had to be installed on the roof to comply with the energy saving ordinance. By the way, we achieved Kfw 70 without any insulation. Just with the bricks and the air-water heat pump. One also has to factor in the additional costs for insulation in case of future renovations. We only need to paint occasionally and do not pay disposal costs for insulation and/or a new insulation. And honestly, I gladly accept the lower soundproofing if I get a house that is significantly more fire-safe as a result. Have you ever seen a house with insulation burning? If not, then just google it. Especially since the soundproofing of a T9 is completely sufficient for a typical new residential area. Sure, the new energy saving ordinance has stricter guidelines; you can no longer make it with a 36 cm brick. And as for the size: whether a child's room is 10 cm bigger or smaller doesn’t really matter, as long as they are not tiny holes.

Whether the necessary compensatory measures are still economically sensible overall in my example (36.5 cm aerated concrete monolithic) I dare to doubt.



Yes, pretty much exactly 9500,- Didn’t you read my previous post? And with my post, I had asked whether the 4200 for additional insulation might possibly pay for itself, so that the gas boiler “only” has to earn back 4300,- (consideration period 10 years).


Uh, yes??? I had already written that too.


I have no advisor, only a seller – and he wants to sell me a house. Whether with gas or air-water heat pump makes no difference to him. And whether the air-water heat pump ends up with an annual performance factor of 1.5 also......


No, it isn’t – see above. Would you also like to answer my question?


In a standard single-family house it often runs together with all the other water pipes on the inside of the utility room upwards, so no loss of space at all.....

And how do you come to the doubt? Do you have all the numbers black on white? Or is it just a feeling?

How did your post calculate the 4200€? Probably just a statement without numbers? Or did he calculate it out for you? Did he consider your financing? What energy price increase did he assume for the next 10 years? What maintenance costs? How does he know which heat pump it will be? Has he already done a heating load calculation?

He does care about what you buy; he wants to sell you what he earns the most on. And how do you come to an annual performance factor of 1-2?

I can’t answer your question. At most, I could name you the parameters I know from my construction project.

Apparently, you didn’t understand what I tried to point out! How should I know whether your thicker roof insulation is worth it? That simply depends on so many factors. It is clear that if you insulate more, you save energy. How much? You have to calculate that yourself... maybe you get a result. How it will look later when the heating is running... you will then see.

Can’t calculate it either? Find someone who does heating load calculations. Give him different numbers for roof insulation, floor insulation, windows, exterior wall, room temperatures, air exchange, etc. The calculation will probably be as expensive as your savings.

Your developer has zero clue! He might know what the raw materials and labor cost, but nothing more. He’s not interested in how economical it ultimately is for YOU. It is economical for HIM (and the bank)! Because he has concrete current numbers and YOU as buyer. With that, the deal is done. YOU only have economy if everything happens as YOU assumed (or as someone like your developer prophesied). And if not? Miscalculated, wrong decision, bad luck! So good luck finding the optimum.

W. Pickartz is certainly not wrong when he says that complying with the Energy Saving Ordinance from next year is already enough to build an energy-efficient and economical house. Just take a look at the requirements of the Energy Saving Ordinance and compare them with the standard house from 1995.

What do you want to tell me with that?

That a KFW100 house from 2016 would have been considered uneconomical nonsense 20 years ago because it was too well insulated.

And? Are you now trying to say they were wrong back then because it is worthwhile today?