Energy Saving Regulation Proof for KfW55 and KfW40

Hello everyone,

we are planning to build a prefabricated house (timber frame) in 2012. We have already obtained several offers. One of them has now sent a heat calculation according to the Energy Saving Ordinance. Once for the standard offer (KfW55) and a second for a KfW40 house.

For the KfW40 house, additional insulation must be applied under the floor slab, the ceiling on the upper floor must be insulated 6 cm thicker, and a solar system would be necessary. Unfortunately, we do not yet have a surcharge for this. How much surcharge would be acceptable here for it to be worthwhile?

I am attaching both calculations here. A Tecalor THZ 303 integral heat pump was offered. Would this be sufficient? After all, it is 168 m²!

I know that the calculation according to the Energy Saving Ordinance is not perfect. However, I probably will not get a calculation according to EN12831 from any company as long as I have not signed anything.

Thanks in advance for your answers.

Regards

murby81

Hello,

For the KfW40 house, additional insulation must be installed under the floor slab, the ceiling on the upper floor must be insulated 6cm thicker, and a solar system would be necessary. Unfortunately, we do not yet have an extra charge for this. Up to what amount would the extra charge have to be for it to be worthwhile?

Honest answer: it will never be worthwhile, because you simply won’t live long enough for the extra effort to pay off; KfW 40 is still something for idealists at the moment

I am attaching both calculations here. A Tecalor THZ 303 integral heat pump was offered. Would that be sufficient? After all, it's 168m²!

The Tecalor comes in different versions, so you shouldn’t worry too much—as long as the calculation matches the actually installed system. To me, the more important question seems to be where you want to install the system? Usually, it doesn’t work in the basement...

I know the calculation according to the Energy Saving Ordinance is not perfect. However, I doubt any company will do a calculation according to EN12831 as long as I haven’t signed anything.

That’s true, and it’s also true that a standardized calculation based on a fictitious house helps you little to nothing; only when "your" house has been calculated by a professional do you have reliable values

Best regards

Hello,

...For a KfW40 house, additional insulation must be applied under the floor slab, the ceiling on the upper floor must be insulated 6cm thicker, and a solar system would be necessary. Unfortunately, we do not yet have a surcharge for this. How much could the surcharge be here so that it is worth it?

The leap from KfW EH55 to KfW EH40 can sometimes be relatively easy to achieve (KfW optimization)! Whether the measures considered above are actually effective, in my opinion not necessarily.

...A Tecalor THZ 303 integral was offered as a heat pump. Would this be sufficient? After all, it is 168m²!

How this specific device can be offered is beyond me! For this, the heating load calculation would already have to be available as a minimum requirement! So, there is nothing to sign here! Moreover, it is not guaranteed that the THZ would actually be the most sensible device. However, the general contractor would like to sell it to you as an "all-round worry-free package." Let him provide a justification as to why exactly this device and no other or manufacturer.
KfW EH 40 has a better standard than a PH according to PHPP!
You can also build a KfW EH 55 and still have a PH, without the generously 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 surcharge to be paid must be taken into account. This (packaging) does not always correspond to what is actually contained in the package.

Regards

Thank you 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. And I have to base myself on something.

Regarding KfW40: The KfW Bank gives an additional €2500 for this. So if the surcharge for the KfW house were €6000, it would effectively only be €3500. Would that make sense within the next 15-20 years? Or am I completely off.

Regarding WP: I really have no clue. 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 in the same house. But the question why and how is legitimate, and I will ask about that.

Hello,

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

Unfortunately, no! However, if one assumes that a system cannot be properly sized without a heating load calculation, any reasonably trustworthy provider should have no problems with this.

....Regarding KfW40: There is an additional €2500 from the KfW bank for this.

One should consider the higher repayment subsidy as a "bonus," not as the sole investment decision. Not a few KfW EH 55 or better on paper are in real practice just EH 70 or Energy Saving Ordinance standard.
The "true" value of a building in the EH40 class is its lower energy consumption over time! However, the "paper data" must also be realized in reality afterward. This is where many general contractors/general planners projects partially struggle significantly.
With a consumption forecast based on the real parameters, the additional investments can be evaluated.

....Regarding WP: I really have zero knowledge. What I do like is that a ventilation system with heat recovery is included. This is already the second provider to offer me this device in the same house.

There is a reason for that. Combi unit, cheap, easy to install! Whereas Combi not only means compact but also compromise. Typical general contractor concept.
Best regards