Heating costs per year KfW55 - KfW70, building decision heating

How can I carry out a heating demand calculation/heating load calculation?

That should rather be left to the MEP planner and energy consultant. Furthermore, the standard heating load alone and exclusively does not provide any usable results.

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Is there an online tool for that?

None, because DIN 12831 (detailed procedure) must be applied. No one will probably give away a valuable benefit. In addition, some experience is required. A large part of the heating load calculations by HVAC engineers or system providers is by the way incorrect, especially if a controlled residential ventilation with/without heat recovery is planned. The preliminary calculation of the actual demand (capacity, energy) for heating and hot water preparation "debunks" many myths circulating.

Best regards.

@DerDa: Thanks for your assessment! A prefab house manufacturer said he only builds KFW55, everything else doesn't make sense, and a solid house manufacturer said he builds a maximum of KfW70 because the additional costs to KfW55 don't make sense. Obviously, they both say that because they want to sell their houses. Now we're struggling with the decision whether KfW55 or KfW70. In terms of living comfort, I don't really care because I don't really notice it anyway. I'm more concerned about the heating costs and how they differ between KfW55 and KfW70... Does anyone else have an assessment on this? Thanks and best regards Herbert

@DerDa: Thanks for your assessment! A prefab house manufacturer said he only builds KfW55, everything else makes no sense, and a solid house manufacturer said he builds a maximum of KfW70, because the additional costs compared to KfW55 don't make sense. Of course, both say that because they both want to sell their houses. Now we are having a hard time deciding whether KfW55 or KfW70. In terms of living comfort, I don't really care because I don't really notice it anyway. I'm more concerned about the heating costs and how they differ between KfW55 and KfW70... Does anyone else have an assessment on this? Thanks and regards Herbert

Good morning,

we are going around in circles here – useful answers have already been given. If I want data/numbers from the manufacturer, he will provide them. That was the case with us. You could compare the numbers for KFW55 and 70 for an identical house, of course with the same heat generator. And if a company does not provide numbers on my request, but works with arguments like above, it is out. Plain and simple.

And keep in mind: the actual heating costs can look different if you want 24 degrees in the living room instead of 19, etc. Then you simply have to have a calculation made by a corresponding planner, for a fee of course. He only needs the data from the house (u-values, floor coverings, controlled residential ventilation/heat recovery, heat generator, target temperatures, location/orientation of the house, windows, persons, etc. etc.) and will then calculate it for you. Then you will come pretty close to your future heating costs.

But for a general comparison KFW 55/70 the information from the companies is sufficient.

My opinion.

Regards...

.... Then you will come pretty close to your future heating costs.

That's right! Modern heating technology requires precise planning anyway if it is to be truly efficient.

.... But for a general comparison KFW 55/70 the information from the companies is sufficient.

I see it a bit differently. Here, something is often "beautified," hardly understandable for laypeople, or energy saving regulations/KfW data are referenced.

That's right! Modern heating technology requires precise planning anyway if it is to be truly efficient. I see it a bit differently. Here, something is often "beautified" in a way that is hardly comprehensible to laypeople, or it relies on energy saving ordinance/KfW data.

v.g.

You may be right about that, but a reasonably reputable provider should be able to provide appropriate data to have a comparison of KFW70/55. Hope dies last.

Regards...

You may be right about that,...

This is certainly always related to the individual case. However, a trend is unmistakable. In proofs, "cooking the books" is done completely legally; practice often looks completely different. Thus, a highly paid EH 55 on paper suddenly just barely meets the Energy Saving Ordinance standard, despite the significantly higher investment costs.

...but a somewhat reputable provider should be able to provide corresponding numerical data to have a comparison KFW70/55.

Yes, the theoretical proofs on paper. They only allow a theoretical, qualitative comparison. Real quantities often turn out quite differently during actual operation afterward. Then good advice is usually very expensive!

best regards