ᐅ New Construction: Verifying Energy Efficiency Certificates / Energy Performance Certificates, Checking Costs

Overall, the costs don’t look very promising.

No, it definitely doesn’t look promising! However, I am definitely not willing to pay 2,000€ if it really is just for the thermal insulation certificate!

The certificate is only a rough guideline, nothing more. Whether the engineer actually chose the most sensible solution cannot be assessed from a distance. For this, a determination of the actual demand based on the chosen building structure, the climate location, and user behavior would be necessary as part of the fundamental assessment. From this actual demand, in connection with the respective technical solution for heating, domestic hot water preparation, and ventilation with heat recovery, the expected consumption can be derived. That alone leads to a reliable evaluation of the necessary investments.
The builder can at best use the certificate for building component geometry and U-values of the components, for controlled residential ventilation with or without heat recovery the determined air volumes according to the air volume plan per DIN 1946-6, and the concept specified by the certificate (heat generator etc.) for their calculations!

Meanwhile, I have also read quite a bit in specialized forums for heating design, and everywhere it is recommended not to select a heating system based solely on the energy performance certificate, since it does not include all the details! Thanks already for the hint here.

The heating load calculation according to DIN 12831 alone is not sufficient, especially when condensing boilers, heat pumps, or pellet heaters are planned as heat generators.
Modern heating systems can be very efficient, but only if a complete and comprehensive sizing and calculation of all components is carried out. This includes, among other things, the heating surfaces and the system hydraulics.
Of course, for an open campfire this is not necessary!

OK, after various online studies I have now read quite a bit that a heating load calculation according to DIN 12831 is important. I think that makes sense, since it includes various other details as you have already mentioned above.
If this is still not sufficient, can you tell me what else is needed besides the energy certificate and the heating load calculation to select the heating capacity?

It is now known that builders of turnkey projects are often taken advantage of regarding the technical systems. This should not be expected with the more expensive independent architectural planning. Apparently, this is where the “quick money” is made at the expense of the builder.

Honestly, this surprises me too, especially since the architect has no benefit if an incorrect heating system is installed. OK, the heating contractor could benefit if they install an oversized heating system based on an incorrect calculation… Understanding this as a layperson is definitely not easy…

Hello,
first of all, I doubt that you need a sound and fire protection certificate for your building. I would generally say no. Also, I find it hard to believe that the thermal insulation certificate alone costs 2,000 euros. And thirdly, the structural engineer does not design your heating system. They only provide proof based on the planning specifications, which are ideally prepared by the architect in collaboration with a building services engineer.

Who hired the structural engineer?

Regards

E.Curb schrieb:
Hello,
first of all, I doubt that you need a soundproofing and fire protection certificate for your building. I would generally say no. Also, I find it hard to believe that the thermal protection certificate alone would cost 2,000 euros. And third, the structural engineer doesn’t plan your heating system. They only provide verification according to the requirements of the design, which is ideally created by the architect in cooperation with an HVAC engineer.

Who hired the structural engineer?

Regards

I think we might have been talking past each other. Of course, the structural engineer isn’t planning the heating system. Our heating contractor is responsible for that, but unfortunately based on the thermal protection certificate, which was actually prepared by the structural engineer. I will definitely have a heating load calculation done to have more detailed information available.

€uro schrieb:
Understandable, since this amount solely for the verification would not be appropriate.
If it is only about the heating load (capacity of the heat generator), the calculation according to 12831 is sufficient. However, for a coherent overall concept, it is not.

Usually, the following is required and also requested or commissioned:

1. Energy-saving regulation / KfW verification – possibly optimization/variants
2. If controlled residential ventilation: air volume plan / ventilation concept according to DIN 1946-6
3. Heating load calculation according to DIN 12831, room heating loads
4. Dimensioning of heating surfaces including radiators / underfloor heating / wall heating / ceiling heating according to DIN (with optimization depending on the heat generator)
5. Dimensioning of domestic hot water preparation
6. Selection / recommendation of heat generator
7. Hydraulic check
8. Demand / consumption forecast
9. Various notes and explanations (including control options for verifying the executing company as well as during later operation.)

Point 8 plays a key role here, since only through this can the investments for individual technical solutions be adequately assessed / evaluated.

Best regards.

Thank you once again for your help; it really helps me to piece together the individual components of my basic knowledge a bit better, as well as to see what I need to pay attention to. Conversations with the architect will definitely still take place regarding how to best solve everything, since this was also one of the reasons for us to work with an architect: to achieve the best possible solution for us.