Heat pump for KfW55 house 148 sqm

And the project is not particularly realistic. Because where do you want to get a heat pump faster in the current situation than your main contractor or his installer? If you knew an installer well enough that he could get it for you, then you would ask him these questions here ;)

I see it the same way. Why is there actually no heat pump available now? And why should you as laypeople succeed faster in getting one than a connected professional?

We were able to read the installation spacing quite well from the squares on the stapler mat. But we simply don’t know what the specification was.

I also don’t realistically see us procuring the heat pump. Because there are quite a few consequences attached to that, like warranty etc.
Our builder or rather their plumber are not exactly shining stars when it comes to making an effort to procure a heat pump. Hands up and sorry, that’s all there is.
Other providers are much more agile, as we can see on neighboring construction sites.
We are just feeling out all directions.
According to friends in Denmark, heat pumps are available there.

But back to an initial question: are the 8kW oversized?
Not that that helps me, because the 8kW are already ordered and will arrive eventually. Switching to a 6kW now would only delay everything further. I just wanted to get your opinion.

And can the Daikin Altherma 3 R F modulate?

But back to an initial question: are the 8kW oversized?

For the house? Definitely. For the installation distance? I think so too. As a DIYer, I would install a 5kW Panasonic monoblock for that house size.
But since you are building with a developer (? - or is it a general contractor), they should take care of it. If the heat pump doesn’t fit, they have to deal with alternatives. You can’t just let them off the hook, especially when it also concerns warranty issues. What contract data is available (construction period, handover, penalties, etc.)? That also plays a big role.

And can the Daikin Altherma 3 R F modulate?

Yes.

P.S. It will of course also work with the larger heat pump. But normally, people prefer something a bit smaller rather than much too big.

The installation spacing is 15cm, in the bathrooms 5-10cm. This is estimated based on photos

Please show one or the other...

All added up, the standard heating load is 6233 W

And why then...

However, the heating load calculation shows an 8kW air-to-air heat pump in the plan.

So we have KFW55 145sqm living space, 2 full floors, and no basement. Spitzbogen cold, so similar conditions. We received a complete heating load calculation where every room including ventilation was calculated. The result was 4090W. So I would also say that 8KW is way too large. With 5KW you would be advised reasonably. Is there no calculation for you?

Before I would accept the hassle, I would simply take the 8KW heat pump. Where do you see the risk? Too big = a bit harder to adjust and will especially cycle in transitional periods => Not a big deal, because your general contractor/plumber probably won’t set the air-water heat pump efficiently anyway, so you will have to deal with this issue regardless with that expectation.

The acquisition costs won’t totally escalate now considering the longer time until everything is finished and that you will also have stress with the general contractor and then have to take care of the heat pump yourself.

I would stay with the heating positions at the general contractor, and something like this should have been considered before starting with a general contractor whether the package suits you or if more individuality is wanted.

PS. We got a 7KW heat pump from the general contractor for 167m2 KFW55 and are satisfied with the efficiency as well as the cycling behavior, although it definitely took some time to adjust it. We could have sized it smaller with better underfloor heating planning, but general contractor after all... that meets with incomprehension.