ᐅ Energy Performance Certificate for KfW55 and KfW40 Standard Compliance

Hello everyone,

We are planning to build a prefabricated house (timber frame) in 2012. We have already requested several quotes. One of them included an energy calculation based on the Energy Saving Ordinance, once for the standard offer (KfW55) and once for a KfW40 house.

For the KfW40 house, additional insulation needs to be installed under the slab, the ceiling on the upper floor must be insulated 6cm (2.4 inches) thicker, and a solar system would be required. Unfortunately, we do not yet have an additional cost for this. How much extra cost would be acceptable here to make it worthwhile?

I am attaching both calculations. A Tecalor THZ 303 integral heat pump was offered. Would this be sufficient? After all, it is for 168m² (1,810 sq ft)!

I know that the Energy Saving Ordinance calculation is not the best standard. However, I don’t think any company will do a calculation according to EN12831 as long as I haven’t signed anything.

Thanks in advance for your answers.

Best regards

murby81

Hello,

murby81 schrieb:
For the KfW40 house, additional insulation must be installed beneath the foundation slab, the ceiling on the upper floor should be insulated 6cm (2.4 inches) thicker, and a solar system would be necessary. Unfortunately, we don’t have an extra cost for this yet. How much extra cost would be reasonable for it to be worthwhile?

Honest answer: it will probably never be worth it because you won’t live long enough for the extra effort to pay off; KfW 40 is still somewhat for idealists at the moment.

murby81 schrieb:
I am attaching both calculations here. A Tecalor THZ 303 integral heat pump was offered. Would this be sufficient? After all, it’s 168m² (1810 sq ft)!

The Tecalor heat pump comes in different versions, so you don’t need to worry much — as long as the calculation matches the actual installed system. A more important question seems to me where you plan to install the system? Usually, installing it in the basement is not feasible...

murby81 schrieb:
I know that the calculation according to the Energy Saving Ordinance is not ideal. However, I guess no company will do a calculation according to EN12831 before I’ve signed anything.

That is correct, and it’s also true that a standardized calculation based on a hypothetical house is of little or no use; only when “your” house has been calculated by a professional will you have reliable values available.

Kind regards

Hello,

murby81 schrieb:
...For the KfW40 house, additional insulation must be applied beneath the slab foundation, the ceiling on the upper floor needs to be insulated 6cm (2.4 inches) thicker, and a solar system would be necessary. Unfortunately, we don’t yet have an additional cost for this. Up to what price increase would it still be worthwhile?

The step from KfW EH55 to KfW EH40 can sometimes be relatively easy to achieve (KfW optimization)! In my opinion, the measures mentioned above are not necessarily actually effective for this.

murby81 schrieb:
...A Tecalor THZ 303 integral heat pump was offered. Would this be sufficient? After all, it’s for 168m² (1808 sq ft)!

I don’t understand how this particular device can be offered! As a minimum requirement, a heating load calculation should already exist for this! Therefore, nothing should be signed here! It is also not guaranteed that the THZ is actually the most appropriate device. However, the general contractor probably wants to sell this to you as a “complete worry-free package.” Let them provide a justification why exactly this device and not another or other manufacturers.
KfW EH40 has a higher standard than a Passive House according to PHPP!
It is also possible to build a KfW EH55 and still have a Passive House without the highly rewarded certification label.
I do not share the opinion of the building expert, because the best energy is that which is not needed. Future energy prices will confirm this. However, the additional cost has to be taken into account. The price (packaging) does not always reflect what is actually included in the package.
Best regards

Thanks for your answers.

Do I have the right to a heating load calculation before I sign anything? Unfortunately, I don’t have any more information available. But I need to base my decision on something.

Regarding KfW40: The KfW bank offers an additional €2,500 (about $2,700) for this standard. So if the extra cost for the KfW house is €6,000 (about $6,500), then effectively it’s only €3,500 (about $3,800). Would that be worth it within the next 15–20 years? Or am I completely off?

Regarding heat pumps: I really have no idea. What I do like is that a ventilation system with heat recovery is included. This is already the second provider offering me this device in the same house. But the questions why and how are valid, and I will definitely ask about that.

Hello,

murby81 schrieb:
..Do I have the right to a heating load calculation before I sign anything?

Unfortunately, no! However, since a system cannot be properly sized without a heating load calculation, any reasonably trustworthy provider should have no problem with this.

murby81 schrieb:
....Regarding KfW40: The KfW bank offers an additional 2500€ for this.

You should consider the higher repayment grant as a bonus, not the sole reason for your investment decision. Many buildings labeled as KfW EH 55 or better on paper are, in practice, closer to EH 70 or the Energy Saving Ordinance standard.
The “real” value of a building in the EH40 class lies in its lower energy consumption over the long term! However, the “paper values” must also be realized in practice. This is where many general contractors (GCs) or building contractors (BCs) encounter significant difficulties in some projects.
With a consumption forecast based on real parameters, the additional investments can be properly evaluated.

murby81 schrieb:
....Regarding heat pumps: I have absolutely no idea. What I do like is that a ventilation system with heat recovery is included. This is already the second provider who has offered me this device for the same house.

There is a reason for that. Combo device, cheap, easy to install! However, combo not only means compact but also compromise. Typical GC approach.

Best regards